An Analysis of Satterley Property Group Pty Ltd and Western Australian Planning Commission [2026] WASAT 39

1. Introduction

On 23 April 2026, the State Administrative Tribunal of Western Australia delivered its decision in Satterley Property Group Pty Ltd and Western Australian Planning Commission [2026] WASAT 39 (Satterley). The Tribunal, constituted by Judge H Jackson (Deputy President) and Mr R Povey (Member), refused an application by Satterley Property Group Pty Ltd to reopen its case after the hearing had concluded and the decision had been reserved.

The decision warrants close attention from practitioners who appear before the SAT and analogous tribunals across Australia. While the Tribunal’s power to permit a party to reopen its case was confirmed as “undoubted”, the decision articulates a substantive threshold that goes well beyond the mere identification of a new argument or legal mechanism. The core principle is that an application to reopen must demonstrate that the new material would actually assist the Tribunal to reach the correct and preferable decision — not merely that it raises an interesting theoretical possibility.

The significance of the decision lies in the Tribunal’s insistence upon a distinction between a promising idea and a properly developed proposal supported by evidence. Satterley’s application proposed to file supplementary submissions identifying a survey-strata subdivision as an alternative mechanism for enforcing vegetation management obligations, but without any supporting evidence. The Tribunal held that submissions alone, unaccompanied by evidence addressing the practical feasibility of the proposal, were insufficient to justify reopening a complex proceeding that had been heard over seventeen days.

The decision is of particular relevance to planning, environment and resources practitioners, but its principles apply wherever an applicant seeks to reopen before the SAT. It is also instructive for practitioners advising clients at the pre-hearing stage, as it reinforces the expectation that parties will present all of their evidence and submissions at the hearing.

2. Relevant Legal Framework

2.1 The SAT Act and the Power to Reopen

The State Administrative Tribunal Act 2004 (WA) (SAT Act) does not expressly confer a power to allow a party to reopen its case. However, as the Tribunal noted at [17], previous iterations of the Tribunal have proceeded on the basis that such a power exists, citing Owners of Island Apartments Strata Plan 52597 and Pindan Pty Ltd [2018] WASAT 2 and Adam and Di Giacomo [2017] WASAT 126.

The statutory basis for the power was identified in Legal Profession Complaints Committee and a Legal Practitioner [2013] WASAT 34, where the Tribunal described the power as “undoubted” and located its source in ss 32(5) and 34(1) of the SAT Act. Section 32(5) empowers the Tribunal to determine “the practice and procedure” to be applied, while s 34(1) permits the giving of “directions at any time in a proceeding and do whatever is necessary for the speedy and fair conduct of the proceeding”. The Tribunal in Satterley agreed with that analysis (at [18]).

The discretionary framework is informed by the Tribunal’s statutory objectives of fairness, expedition and informality in s 9 and the obligation of procedural fairness in s 32(1), which are consistent with the broad procedural power in s 34(1) (at [19]).

2.2 The Westgem Principles

The Tribunal endorsed the approach of the courts to applications to reopen a party’s case in judicial proceedings, following Re Confidential and Commissioner of Taxation [2013] AATA 382; 61 AAR 293 (at [132]), which held that such principles “provide a useful guide” because “broadly, they are founded in the notion of fairness or natural justice” (at [21]).

Central to the analysis was the decision of Tottle J in Westgem Investments Pty Ltd v Commonwealth Bank of Australia Ltd [No 5] [2019] WASC 310 (Westgem). His Honour identified the overriding principle as whether “the justice of the case favours the grant of leave” (at [63]), and set out seven considerations relevant to an application to reopen where the decision has been reserved but not determined and the purpose is to overcome an error by a party’s lawyers (at [89]):

(a) the public interest (and the interests of the particular parties) in litigation being conducted efficiently and expeditiously;

(b) the public interest in the finality of litigation, with the consequent expectation that litigants will present all their evidence and submissions at the one hearing;

(d) the explanation for the evidence not having been led at the trial;

(e) the likely prejudice to the opposing party if the application is allowed;

(f) the potential detriment to the applying party if the application is refused; and

(g) any delay by an applicant in seeking leave to reopen.

The Tribunal accepted these principles as applicable to the SAT, subject to the observation that they must be read in the context of the relevant provisions of the SAT Act (at [21]–[23]).

3. The Facts of the Case

3.1 The Proposed Structure Plan and the Bushfire Issue

The proceeding concerned Satterley’s application for review of the WAPC’s refusal to approve a proposed Structure Plan for a site that could “reasonably be described as ‘extraordinary’” (at [45]). The site covered 534 hectares, proposed 1,001 lots to accommodate approximately 2,803 people, included two schools, and was anticipated to be staged over more than 15 years. Central to the refusal was whether the development could proceed in a manner such that the risk to people and property from bushfire was acceptable (at [2]).

Satterley’s proposed Structure Plan included a Bushfire Management Plan (BMP) that required certain vegetation to be managed and maintained in a “low threat state” (at [3]). Both the 2024 BMP and the updated 2025 BMP identified the need for a landscape management plan at subdivision stage that would detail responsibilities and provide “an appropriate means of enforcement for the ongoing management of vegetation across the site, especially APZs and low threat vegetation on private land and POS” (at [28]–[30]).

The WAPC had long considered this approach inadequate. Its Statement of Issues, Facts and Contentions contended that the critical assumption — that certain parts of the Structure Plan area would be modified to a low threat state and maintained in that state in perpetuity — was “unjustified and inappropriate” (at [31]).

3.2 The Hearing and the Enforceability Issue

The proceeding was heard over 17 days commencing in September 2025, with final closing submissions made on 11 December 2025 (at [5]). The enforceability of obligations to maintain vegetation in a low threat state was a live issue throughout. Satterley’s witness, Mr Rowe, proposed methods including restrictive covenants on title (at [32]). The WAPC’s witness, Mr Parker, considered that a landscape management plan should be prepared to support the proposed Structure Plan (at [33]). The issue was the subject of expert conferral and cross-examination (at [35]–[36]).

3.3 The Application to Reopen

On 27 February 2026, Satterley applied for leave to reopen its case to file supplementary submissions identifying an “alternate mechanism”: subdivision of private lots as a survey-strata scheme under the Strata Titles Act 1985 (WA), rather than by freehold subdivision (at [7]–[10]). The draft submissions relied on three benefits of the strata mechanism: first, that strata by-laws can impose positive obligations on owners; secondly, that enforcement occurs in the Tribunal rather than the Supreme Court; and thirdly, that enforcement can be initiated by the strata company or individual owners, not just individual lot owners (at [41]).

Mr McGlue, Satterley’s solicitor, deposed that the idea arose the day after closing submissions when he discussed the matter with a partner at his firm with expertise in strata matters (at [38]). The delay between 12 December 2025 and the 27 February 2026 application was explained by the need to consider the matter, discuss with counsel, take instructions, and the intervening Christmas period (at [39]).

Critically, Satterley’s position was that, if leave were granted, it would simply file the draft submissions without calling any evidence (at [13]–[14]).

4. Analysis of the Tribunal’s Reasoning

4.1 The Primary Ground: Submissions Without Evidence Cannot Assist

The Tribunal’s primary reason for refusing leave was that the proposed supplementary submissions, standing alone, would be “insufficient to allow us to make the finding which, if leave were granted, Satterley says it would press upon us” — namely, that “a survey-strata subdivision approach would be appropriate in the circumstances” (at [43]). The Tribunal held that before it could reach such a conclusion, it would need evidence as to whether such an approach was “otherwise suitable in the circumstances of this case” (at [44]).

This reasoning establishes a clear principle: an application to reopen must do more than identify a new legal mechanism. The party must demonstrate that it can place before the Tribunal material sufficient to allow the Tribunal to act upon it. The Tribunal drew a firm distinction between a proposition that is legally possible (“there is nothing in the relevant planning regime — statutory and policy — that precludes it”: at [47]) and one that is practically feasible and evidentially supported.

4.2 The Extraordinary Nature of the Proposal

The Tribunal emphasised the extraordinary scale of both the Structure Plan and the proposed survey-strata mechanism. A survey-strata subdivision covering 534 hectares, 1,001 lots, two schools, and a development staged over 15 years was described as “equally extraordinary” (at [46]) and “appears to be unprecedented” (at [47]). This context heightened the evidentiary burden: the more novel and ambitious the proposal, the more the Tribunal required by way of evidence to satisfy itself that the approach was workable.

4.3 The WAPC’s Unanswered Questions

The Tribunal accepted that the questions raised by the WAPC in its written submissions “raise matters of a nature that should be properly considered” before the Tribunal could reach the conclusion Satterley urged (at [49]). Those questions included whether a single or multiple survey-strata schemes were proposed, how they would interact, whether it was practical over a 15-year staging period, what would be included (particularly roads and open space), how common property would be funded and insured, and whether the proposal was consistent with the Strata Titles Act and planning policy (at [48]).

The Tribunal observed that the survey-strata approach, while it might overcome difficulties with restrictive covenants, “may well raise other difficulties which, at present, remain unidentified or unexplored” (at [50]). Satterley’s proposed approach “does not acknowledge, let alone address, that possibility” (at [51]).

4.4 The Obligation to Put Forward a Considered Proposal

At [57], the Tribunal articulated the standard that applies: the applicant must “put forward a considered proposal, one that fleshes out and explains what is proposed and how it will work, against relevant planning policies”. Where matters are not agreed and are significant, this “will also require the calling of witnesses to express opinions which are explained and to answer questions posed by others”. This passage is likely to be cited frequently in future applications to reopen.

4.5 The Secondary Grounds

The Tribunal also considered the Westgem factors. It accepted Mr McGlue’s explanation of the delay but observed that it was “surprising” that alternative enforcement mechanisms had not received more thorough consideration given “the history of the matter and the significance of the issue” (at [63]). Satterley “was aware of the Issue for a long time, is not without resources, and has been legally represented throughout the proceeding” (at [64]).

The public interest in efficient litigation and finality both weighed against reopening (at [66]). As to prejudice, the Intervenor (Save Perth Hills) noted the “very considerable interest of its members in the prompt resolution of the matter” and that further evidence would cause delay “measured in months, not weeks” (at [68]).

5. Assessing the Consequences

The practical consequences of the decision are significant for the parties and for future applicants.

For Satterley, the refusal means that the Tribunal will determine the proceeding on the evidence and submissions as they stood at the close of the hearing on 11 December 2025. The survey-strata mechanism will not be considered. If the Tribunal ultimately finds that the enforceability of vegetation management obligations is a critical deficiency in the proposed Structure Plan, Satterley will bear the consequences of not having raised the survey-strata alternative during the hearing.

The decision also illustrates the cost of a “wait and see” approach to evidence preparation. The 17-day hearing, involving multiple experts and extensive conferral, represented a substantial investment of time and resources by all parties. The Tribunal’s refusal to reopen underscores that such investment carries with it an expectation of finality. As the Tribunal observed, the other parties were “entitled to proceed on the basis that Satterley’s case will be as outlined in its SIFC and the witness statements of its experts, and that it will not be necessary to come back for a ‘second bite of the cherry’” (at [65]).

The temporal cost of reopening was also a factor. The Intervenor’s submission that further evidence would cause delay measured in months, not weeks, was accepted (at [68]). In complex planning proceedings where community interests are engaged, the delay occasioned by reopening is not merely a matter of inconvenience but engages the statutory objective of expedition.

6. Worked Example

Consider a hypothetical applicant, Greenfield Developments Pty Ltd, which seeks review of the WAPC’s refusal to approve a structure plan for a 200-hectare residential development in a bushfire-prone area. The hearing is conducted over eight days and the decision is reserved. During the hearing, Greenfield’s case was that bushfire risk could be managed through a combination of building standards and landscaping obligations enforced by the local government under local planning policies.

Two weeks after closing submissions, Greenfield’s solicitor identifies a recent amendment to the relevant local planning scheme that introduces a Special Control Area with enforceable conditions directly relevant to vegetation management. Greenfield wishes to reopen to file submissions relying on the new provision.

Analysis from Greenfield’s perspective

Greenfield’s application would be strengthened, relative to Satterley’s, if it were to: (a) tender evidence from a planning witness explaining how the Special Control Area provisions would operate in practice on the specific site; (b) demonstrate that the new provisions address the specific enforceability concerns raised during the hearing; and (c) address any new issues that the mechanism might raise. Applying the principles in Satterley, Greenfield must put forward a “considered proposal” (at [57]) — not merely identify the new provision and submit that it solves the problem.

Analysis from the respondent’s perspective

The WAPC would be entitled to point to the Westgem factors: the public interest in finality, the expectation that Greenfield would present its full case at the hearing, and the delay that reopening would occasion. The WAPC could further argue that the Special Control Area amendment was publicly notified before the hearing and Greenfield’s failure to identify it reflects inadequate preparation, engaging the principle that parties are “entitled to proceed on the basis that [the applicant’s] case will be as outlined in its SIFC” (at [65]).

Likely outcome

If Greenfield proposes to call evidence and can demonstrate that the Special Control Area provision materially changes the analysis on a contested issue, the application has reasonable prospects. If, however, Greenfield merely proposes to file submissions without evidence — as Satterley did — the application is likely to fail. The distinction drawn in Satterley between a promising idea and a considered, evidence-supported proposal is the critical dividing line.

7. Practitioner Guidance: A Step-by-Step Framework

Step 1. Identify the new material and assess its significance. Before applying to reopen, the practitioner must identify precisely what new evidence or submissions are proposed and assess their significance “in the context of the trial” (Westgem at [89](c)). The new material must be capable of making a material difference to the Tribunal’s determination. A new argument that merely repackages existing submissions in different form is unlikely to satisfy this threshold.

Step 2. Prepare the evidence, not just the submissions. The core lesson of Satterley is that identifying a new legal mechanism is not enough. The Tribunal required evidence as to whether the survey-strata approach was “otherwise suitable in the circumstances of this case” (at [44]). Practitioners must ensure that any application to reopen is accompanied by evidence that addresses the feasibility and practicality of the proposal, not merely its theoretical availability.

Step 3. Anticipate and address objections. The Tribunal found it significant that the WAPC’s questions were left unanswered by Satterley’s proposed submissions (at [49]–[51]). Practitioners should identify the questions that the new material will provoke and ensure that the evidence addresses them. A proposal that “does not acknowledge, let alone address” the difficulties it may create (at [51]) will not satisfy the threshold.

Step 4. Provide a frank explanation for the omission. The explanation for the evidence not having been led at the hearing is a relevant factor (Westgem at [89](d)). In Satterley, the Tribunal accepted Mr McGlue’s explanation but observed that it was “surprising” that alternatives had not been more thoroughly considered given the significance of the issue and the resources available to Satterley (at [63]–[64]). Practitioners should be candid in their explanation and avoid overstating the novelty of the omitted material.

Step 5. Act promptly. Delay weighs against the grant of leave (Westgem at [89](g)). While the Tribunal in Satterley did not treat the delay as determinative, it accepted that some criticism could be made (at [62]). Practitioners should apply to reopen as soon as reasonably practicable and document the reasons for any intervening delay.

Step 6. Consider the impact on other parties. The likely prejudice to opposing parties and interested parties is relevant (Westgem at [89](e)). In Satterley, the Intervenor’s submission that further evidence would cause delay “measured in months, not weeks” was accepted (at [68]). Practitioners should be prepared to explain how the reopening can be accommodated without disproportionate delay or prejudice.

Step 7. Frame the application in terms of the correct and preferable decision. The Tribunal’s overriding concern was whether granting leave would “assist us in seeking to reach the correct and preferable decision” (at [59]). Practitioners should frame the application in those terms, demonstrating that the new material is not merely helpful to the applicant but necessary for the Tribunal to discharge its statutory function.

8. Evidence and Arguments Available to Each Side

8.1 For the Party Seeking to Reopen

The party seeking to reopen should consider the following evidence and arguments:

Expert evidence on feasibility. The absence of expert evidence was fatal to Satterley’s application. A party seeking to reopen should tender expert evidence that addresses not only the theoretical availability of the new mechanism but its practical suitability in the specific circumstances. In a planning context, this might include town planning evidence, engineering evidence, legal evidence on the operation of the proposed mechanism, and financial evidence on its implementation costs.

Evidence addressing objections. The new evidence should pre-emptively address the questions likely to be raised by opposing parties. In Satterley, the WAPC raised detailed questions about the operation of the survey-strata mechanism (at [48]) that Satterley’s submissions did not answer. A well-prepared application would address these questions in advance.

Submissions on procedural fairness. The applicant can argue that the Tribunal’s statutory obligation of procedural fairness (s 32(1) SAT Act) and its obligation to reach the “correct and preferable decision” favour permitting the new material. The applicant should emphasise any change in circumstances or new information that was not reasonably available before the hearing closed.

8.2 For the Party Opposing Reopening

Finality and efficiency. The responding party can invoke the public interest in the finality of litigation and the expectation that litigants will present their full case at the hearing (Westgem at [89](a)–(b)). Where the applicant is well-resourced and has been legally represented throughout, the argument carries particular force (at [64]).

Insufficiency of the proposed material. Following Satterley, the responding party can argue that the proposed new material is insufficient to assist the Tribunal. If the applicant proposes submissions without evidence, the respondent can point to [43]–[44] of the decision and submit that the threshold has not been met.

Prejudice and delay. The responding party should quantify the likely delay and its impact. In Satterley, the submission that delay would be “measured in months, not weeks” was effective (at [68]). If the new material would require the opposing party to call responsive evidence, the costs and disruption of doing so are relevant.

Second bite of the cherry. Where the omitted material relates to an issue that was squarely in contest during the hearing, the respondent can argue that the applicant is seeking a “second bite of the cherry” (at [65]) and that the other parties were entitled to rely on the finality of the hearing as conducted.

9. Key Takeaways for Legal Practice

1. The power to reopen is confirmed but its exercise is restrained. The Tribunal confirmed that it has power to allow a party to reopen, sourced in ss 32(5) and 34(1) of the SAT Act. However, the power is to be exercised in accordance with the statutory objectives of fairness, expedition, and the principles identified in Westgem (at [17]–[23]).

2. Submissions without evidence will generally be insufficient. The most significant principle in the decision is that an application to reopen supported only by submissions, without accompanying evidence, is unlikely to succeed where the new proposal raises factual questions about feasibility and suitability (at [43]–[44]).

3. The applicant must put forward a “considered proposal”. The new material must “flesh out and explain what is proposed and how it will work” against relevant policies and frameworks. A bare identification of a theoretical mechanism is not sufficient (at [57]).

4. Novelty heightens the evidentiary burden. Where the proposed new approach is unprecedented or extraordinary, the Tribunal will require correspondingly more rigorous evidence to satisfy itself that it is workable (at [45]–[47]).

5. A new mechanism may solve one problem but create others. The Tribunal cautioned that while a survey-strata approach might overcome the difficulties with restrictive covenants, it “may well raise other difficulties which, at present, remain unidentified or unexplored” (at [50]). Practitioners must address the full implications of any new proposal.

6. Well-resourced, represented parties face a higher expectation. The Tribunal’s observation that Satterley “was aware of the Issue for a long time, is not without resources, and has been legally represented throughout” (at [64]) suggests that the standard of preparation expected of well-funded litigants is higher. The failure to identify alternatives at the hearing stage is more difficult to excuse.

7. The interests of third parties are relevant. The Intervenor’s submission regarding the impact on its members and the likely delay was accepted (at [68]). Practitioners should be alert to the interests of intervenors, interested parties, and the broader community when assessing the prospects of an application to reopen.

8. Pre-hearing preparation is the primary safeguard. The decision reinforces the fundamental principle that thorough preparation before and during the hearing is the most effective protection against the need to reopen. The expectation that parties will present “all their evidence and submissions at the one hearing” (Westgem at [89](b)) is not merely a procedural preference but a principle grounded in fairness and the public interest.

9. The SAT will apply court-derived principles, adapted to its statutory context. The Tribunal’s adoption of the Westgem factors, subject to the SAT Act, confirms that practitioners can look to court authority for guidance on reopening applications, while recognising that the Tribunal’s statutory objectives may modulate their application (at [20]–[22]).