Legal Insight: Third-Party Intervention In Planning Decisions And Its Impact On Civil Construction Projects

By Michelle Todd, Senior Associate

A recent decision by the State Administrative Tribunal (Tribunal) in Satterley Property Group Pty Ltd v Western Australian Planning Commission [2025] WASAT 17 (Satterly) offers an interesting development which may impact the Civil Construction industry. While largely about the proposed North Stoneville Structure Plan No 34 (SP34), the case highlighted the increasing influence of third-party interventions in planning decisions.

Background

The case involved the North Stoneville Structure Plan No 34 (SP34), originally approved in 1998 and set to expire in October 2025. Satterley Property Group (SPG) proposed a ~535-hectare urban development in the Perth Hills, including 1,000 dwellings, open space, and associated amenities. The Western Australian Planning Commission (WAPC) refused the proposal, citing inadequate bushfire risk and traffic impact assessments. Despite submitting a revised plan, the WAPC maintained its refusal.

During the Tribunal review, both the Shire of Mundaring (the Shire) and community group Save Perth Hills (SPH) sought to intervene. The Tribunal granted them leave, finding they had a “sufficient interest” in the matter. SPH demonstrated its long-standing involvement in local planning and bushfire advocacy, while the Shire had statutory responsibilities related to planning, traffic, and bushfire management.

Third-Party Participation

The Tribunal found that the involvement of SPH and the Shire would assist in resolving the issues without unduly affecting the proceedings. Their participation brought valuable insights, particularly regarding bushfire evacuation behaviour and the scale of the proposed development, which would double the population of Stoneville. The overlap in expert witnesses between SPH and WAPC further supported their inclusion.

Implications for Developers and Planners

The Satterley decision underscores the increasing scrutiny that third-party interventions can bring to planning approvals. Their involvement often leads to more rigorous assessments, which can delay project timelines and introduce unexpected challenges. Developers must anticipate these risks early in the planning process and allocate sufficient resources to manage potential disruptions. Legal and procedural complexities also increase when third parties are involved, requiring developers to remain agile, well-informed, and responsive to evolving regulatory expectations.

Equally important is the role of community engagement. The case highlights how local opposition, if not addressed proactively, can escalate into formal objections or legal challenges that significantly influence project design, scope, and scheduling. Developers must engage meaningfully with stakeholders from the outset, ensuring transparency and responsiveness to community concerns. Strategic planning that incorporates comprehensive risk assessments and aligns with planning policies is essential. By considering the broader social and environmental context, developers can reduce opposition, facilitate smoother approvals, and enhance the overall success of their projects.

Conclusion

The Satterley decision illustrates the growing role of third-party stakeholders in planning processes. For the civil construction industry, it is a reminder that successful project delivery begins with thorough planning, legal compliance, and proactive stakeholder engagement. As regulatory frameworks evolve and community voices gain prominence, developers must navigate these dynamics with diligence and foresight to ensure project success.

*This information serves as a general guide and does not constitute legal advice. It is based on our research and experience at the time of publication. Please consult our knowledgeable legal team for any specific inquiries or advice relevant to your circumstances, as the content may not have been updated subsequently.

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