Legislative Powers of the Commonwealth

Introduction

The Commonwealth Parliament is a legislature of enumerated powers. Unlike the State Parliaments, which possess plenary legislative authority, the Commonwealth may only enact laws with respect to the subjects specified in the Constitution. The principal source of Commonwealth legislative power is s 51, which lists 39 specific heads of power (or “subjects”) upon which the Parliament may legislate. Additional legislative powers are conferred by s 52 (exclusive powers over the seat of government and Commonwealth property), s 122 (the Territories power), and other specific provisions. The characterisation of legislation — determining whether a law falls within a head of power — is a fundamental question of Australian constitutional law, and the High Court’s approach to characterisation has shaped the balance of federal power.

The Heads of Power Under Section 51

Section 51 provides that “the Parliament shall, subject to this Constitution, have power to make laws for the peace, order, and good government of the Commonwealth with respect to” the enumerated subjects. The most significant heads of power include:

Trade and commerce (s 51(i)) empowers the Commonwealth to regulate interstate and overseas trade and commerce, though not intrastate trade. Taxation (s 51(ii)) confers power to impose taxes, but not so as to “discriminate between States or parts of States.” Defence (s 51(vi)) confers power over the naval and military forces and the defence of the Commonwealth. External affairs (s 51(xxix)) has been construed expansively to encompass relations with other countries, matters geographically external to Australia, and the implementation of international treaties. The corporations power (s 51(xx)) confers power over foreign corporations and trading or financial corporations formed within the limits of the Commonwealth. The aliens power (s 51(xix)) confers power over naturalisation and aliens. The marriage power (s 51(xxi)) and divorce and matrimonial causes power (s 51(xxii)) together confer comprehensive authority over family law.

Other significant heads include postal, telegraphic, telephonic, and other like services (s 51(v)), banking (s 51(xiii)), insurance (s 51(xiv)), conciliation and arbitration for the prevention and settlement of industrial disputes (s 51(xxxv)), and social security (s 51(xxiiiA), inserted by referendum in 1946). The race power (s 51(xxvi)) originally permitted laws for people of “any race, other than the aboriginal race in any State,” but was amended by the 1967 referendum to remove the exclusion of Aboriginal people, and now permits laws for people of “any race for whom it is deemed necessary to make special laws.”

The Incidental Power

Section 51(xxxix) confers power to make laws with respect to “matters incidental to the execution of any power vested by this Constitution in the Parliament or in either House thereof, or in the Government of the Commonwealth, or in the Federal Judicature, or in any department or officer of the Commonwealth.” This incidental power is not a separate head of power but rather an adjunct to every Commonwealth legislative and executive power. It permits the Parliament to enact laws that are reasonably necessary or appropriate and adapted to give effect to a substantive head of power. For example, the incidental power supports laws that prohibit conduct with a sufficient connection to interstate trade, or that create offences for interfering with the exercise of a Commonwealth power.

Characterisation of Laws

The question whether a law is within Commonwealth power is determined by the process of characterisation. The High Court’s modern approach, established in Grain Pool of Western Australia v Commonwealth (2000) 202 CLR 479, is a textual approach: the court examines the legal and practical operation of the law to determine whether it is a law “with respect to” a head of power. The court asks whether there is a sufficient connection between the law and the head of power. This is assessed by reference to the law’s direct legal operation — its rights, duties, powers, and privileges — rather than its indirect economic or social effects.

Some heads of power are purposive, meaning that a law must be not only sufficiently connected to the subject matter but also appropriate and adapted (or proportionate) to the purpose of the power. The defence power (s 51(vi)) is the paradigmatic purposive power: its scope expands during wartime and contracts in peacetime. The external affairs power (s 51(xxix)), when used to implement treaties, is also purposive: the law must be “reasonably capable of being considered appropriate and adapted” to implementing the treaty obligation (see Victoria v Commonwealth (1996) 187 CLR 416, the Industrial Relations Act Case).

The High Court has rejected the requirement of proportionality for non-purposive powers in the context of characterisation. In Leask v Commonwealth (1996) 187 CLR 579, the Court held that proportionality is relevant to the characterisation of purposive powers but not to non-purposive powers, where the question is simply whether there is a sufficient connection between the law and the subject matter of the power.

Dual Characterisation

A law may have more than one character; it may be a law with respect to multiple heads of power, or with respect to a head of power and also with respect to a matter beyond Commonwealth power. The principle of dual characterisation holds that a law will be valid if it can be characterised as a law with respect to a Commonwealth head of power, even if it can also be characterised as a law with respect to a matter within State competence. In Murphyores Incorporated v Commonwealth (1976) 136 CLR 1, the Court upheld a law prohibiting the export of mineral sands without ministerial consent, even though the law was clearly directed at environmental regulation (a State matter), because it could be characterised as a law with respect to overseas trade and commerce under s 51(i).

Exclusive and Concurrent Powers

The Commonwealth’s legislative powers are primarily concurrent with those of the States; both the Commonwealth and the States may legislate on the subjects listed in s 51. However, certain powers are exclusive to the Commonwealth, including the power to legislate with respect to the seat of government (s 52(i)), the public service (s 52(ii)), customs and excise duties (s 90), and the raising of naval and military forces (s 114). Where Commonwealth and State laws conflict, s 109 provides that Commonwealth law prevails and the State law is invalid to the extent of the inconsistency.

The States retain residual powers — that is, all legislative capacity not conferred on the Commonwealth or withdrawn from the States by the Constitution. These include powers over property law, contract law, tort law, criminal law (generally), education, health, local government, and land use planning. The federal balance between Commonwealth and State legislative power has shifted significantly since Federation, with the Commonwealth’s powers expanding through judicial interpretation (particularly of the external affairs and corporations powers) and through financial dominance (via s 96 grants).