Western Australian Planning Commission v. Leith; Western Australian Planning Commission v. Southregal Pty Ltd & Anor

The Western Australian Planning Commission (WAPC) appealed to the High Court of Australia against decisions of the Supreme Court of Western Australia concerning the validity of certain planning approvals. The primary dispute involved the WAPC's contention that the Supreme Court had erred in its interpretation of the *Environmental Protection Act 1986* (WA) and the *Planning and Development Act 2005* (WA) in relation to the approval of a development. The respondents, Leith and Southregal Pty Ltd, argued that the WAPC's actions were unlawful.

The High Court was required to determine whether the WAPC had lawfully exercised its powers under the *Environmental Protection Act 1986* (WA) when it granted planning approval for a development, notwithstanding that the development had not been referred to the Environmental Protection Authority for assessment as required by that Act. Specifically, the Court had to consider the interplay between the referral requirements of the *Environmental Protection Act 1986* (WA) and the WAPC's powers to grant planning approval under the *Planning and Development Act 2005* (WA).

Kiefel and Nettle JJ held that the *Environmental Protection Act 1986* (WA) imposed a mandatory requirement for referral to the Environmental Protection Authority for assessment of proposals likely to have a significant impact on the environment. They reasoned that the WAPC could not lawfully grant planning approval for a development that had not undergone this mandatory referral process. The Court emphasised that the statutory scheme under the *Environmental Protection Act 1986* (WA) was designed to ensure environmental considerations were addressed before development approvals were granted, and this requirement could not be circumvented by the WAPC.

The High Court allowed the appeals, setting aside the decisions of the Supreme Court of Western Australia.