It is time to reconsider how public law affects government contracting. Concepts of ‘the Crown’ or ‘the prerogative’ do not assist. Instead, the issues are, and must be seen as, issues about structure of government. Federal considerations limit the Commonwealth’s power to contract. The Commonwealth executive has constitutional power to make contracts for administering the departments of state. So, too, do the states. But the structure of the federal and state constitutions may require that the executive not make substantial contracts without legislative authority. In addition, it may be doubted that the legislature may authorise a contract by which the polity, or an organ of government, promises to bind future administrations.
The Hon KM Hayne AC, Government Contracts and Public Law, Melbourne University Law Review (2017–18) volume 41.