Pilbara Infrastructure Pty Ltd & Anor v Australian Competition Tribunal Ors; The National Competition Council v Hamersley Iron Pty Ltd & Ors; The National Competition Council v Robe River Mining Co Pty Ltd & Ors

The High Court of Australia considered appeals from decisions of the Australian Competition Tribunal concerning access undertakings given by Pilbara Infrastructure Pty Ltd (Pilbara Infrastructure) and Hamersley Iron Pty Ltd (Hamersley Iron) and Robe River Mining Co Pty Ltd (Robe River) under Part IIIA of the *Competition and Consumer Act 2010* (Cth). The National Competition Council (NCC) had recommended that the Minister for Infrastructure and Transport (the Minister) not accept these undertakings, and the Minister had subsequently decided not to accept them. Pilbara Infrastructure, Hamersley Iron, and Robe River appealed these decisions to the Tribunal, which set aside the Minister's decisions and accepted the undertakings. The NCC and the Minister then appealed to the High Court.

The central legal issue before the High Court was whether the Tribunal had erred in law by setting aside the Minister's decisions not to accept the access undertakings. This involved determining the proper scope of the Tribunal's review powers under section 44ZZX of the Act, specifically whether the Tribunal was entitled to substitute its own assessment for that of the Minister and the NCC, or whether its review was limited to assessing the legality of the Minister's decision-making process. The Court also considered the interpretation of the criteria for accepting an access undertaking, particularly the requirement that an undertaking must be 'likely to be effective' in promoting the objects of Part IIIA.

The High Court, by majority, held that the Tribunal had erred in law. The Court reasoned that the Tribunal's review of the Minister's decision was not a broad merits review but was confined to the legality of the decision. The Tribunal had impermissibly substituted its own view for that of the Minister and the NCC on matters of policy and commercial judgment, which were within the Minister's purview. The Court emphasised that the Minister's decision not to accept an undertaking, provided it was made for a relevant purpose and in accordance with the Act, was not amenable to being overturned simply because the Tribunal disagreed with the outcome. The principles of administrative law concerning the scope of review of executive decisions were central to the Court's reasoning.

The High Court allowed the appeals, set aside the orders of the Australian Competition Tribunal, and remitted the matters to the Tribunal for further consideration according to law.