Federation and the division of powers

The short answer

Federation and the division of powers

Australia is a federation of six states and two self-governing territories. The Australian Constitution, which came into effect on 1 January 1901, establishes a federal system of government that divides legislative powers between the Commonwealth Parliament and the state parliaments. The Commonwealth has only those powers specifically granted to it by the Constitution — these are largely set out in section 51, which lists 39 subjects on which the Commonwealth may legislate, including taxation, defence, trade and commerce, immigration, and marriage. The states retain broad residual authority over all matters not expressly given to the Commonwealth, such as education, health, criminal law, and land management. In practice, many policy areas involve overlapping Commonwealth and state responsibilities, supported by tied grants under section 96, intergovernmental agreements through the National Cabinet, and cooperative federalism arrangements. The High Court of Australia interprets the Constitution and resolves disputes over the division of powers.

This is a federal system guide. State constitutions, parliaments and local-government laws can allocate comparable functions differently.

The useful question is not only “what is the rule?” but also “who administers it, which document controls it, and when might it change?” That distinction prevents an accurate general explanation from becoming wrong advice in a particular election, chamber or policy setting.

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The origins of Australian federation

Before 1901, the Australian continent consisted of six separate British colonies — New South Wales, Victoria, Queensland, South Australia, Western Australia, and Tasmania — each with its own parliament, laws, tariffs, postal system, and defence forces. The movement for federation gained momentum through the 1890s, driven by practical concerns about trade barriers between colonies, the need for a coordinated defence strategy, and a growing sense of national identity. Two constitutional conventions were held in 1891 and 1897-1898, where delegates from each colony negotiated the terms of union. The resulting draft Constitution was put to referendums in each colony, and after it was approved by the people, the British Parliament passed the Commonwealth of Australia Constitution Act 1900. The Commonwealth of Australia came into being on the first day of the new century, 1 January 1901. Significantly, the Constitution established a federal rather than a unitary system — the former colonies became states that retained their own constitutions, parliaments, and substantial legislative powers.

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The constitutional division of legislative power

The Australian Constitution divides legislative power between the Commonwealth and the states by specifying what the Commonwealth Parliament may do. Section 51 of the Constitution lists 39 specific subject matters — often called heads of power — on which the Commonwealth may make laws. These include trade and commerce with other countries and among the states (section 51(i)), taxation (section 51(ii)), defence (section 51(vi)), quarantine (section 51(ix)), postal and telecommunications services (section 51(v)), currency (section 51(xii)), marriage (section 51(xxi)), immigration (section 51(xxvii)), and external affairs (section 51(xxix)). The Commonwealth also has exclusive powers under sections 52 and 90, including the power to impose customs and excise duties. Everything not listed in section 51 or the other specific grants of power remains with the states. This is the residual powers doctrine — the states retain authority over all areas of law and policy that the Constitution does not assign to the Commonwealth.

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State powers and responsibilities

State parliaments retain broad legislative competence over the areas of daily life that most directly affect Australians. State responsibilities include public hospitals and the health system, primary and secondary education, police and criminal law, roads and public transport, land use planning and development, and utilities such as water and electricity. State parliaments also have their own constitutions, although these are subject to the Commonwealth Constitution and Commonwealth laws validly made under it. The states have their own court systems, with state supreme courts exercising general jurisdiction over civil and criminal matters. Importantly, under section 109 of the Constitution, if a valid Commonwealth law is inconsistent with a state law, the Commonwealth law prevails to the extent of the inconsistency. This provision can operate to override state laws where the Commonwealth has legislated within one of its constitutional heads of power.

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Concurrent powers and cooperative federalism

Most of the Commonwealth's powers under section 51 are concurrent rather than exclusive, meaning that both the Commonwealth and the states can legislate on the same subject. Where this occurs, section 109 of the Constitution resolves conflicts in favour of the Commonwealth. In practice, many areas of Australian governance involve shared or overlapping responsibilities between the Commonwealth and the states, a model often described as cooperative federalism. The Commonwealth uses its financial power under section 96 of the Constitution to make grants to the states on terms and conditions it determines — known as tied grants. Through tied grants, the Commonwealth can influence state policy in areas that are otherwise within state jurisdiction, such as hospital funding, school education, and housing. Intergovernmental cooperation is formalised through bodies such as the National Cabinet, which brings together the Prime Minister and state and territory first ministers to coordinate national policy responses.

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The role of the High Court

The High Court of Australia is the ultimate arbiter of the division of powers under the Constitution. It has the power to determine whether a Commonwealth law is validly made within a head of power and whether a state law is inconsistent with a valid Commonwealth law. The High Court's interpretations of the Constitution have shaped Australian federalism in profound ways. In the Engineers Case of 1920, the Court abandoned the doctrine of implied immunity of instrumentalities, which had previously limited the reach of Commonwealth laws over state governments. Subsequent decisions have generally taken an expansive view of Commonwealth powers, particularly the corporations power (section 51(xx)) and the external affairs power (section 51(xxix)), which have been interpreted broadly enough to support Commonwealth legislation on workplace relations, environmental protection, and human rights. The High Court's decisions are binding on all other Australian courts and can only be altered by a constitutional referendum or, in some cases, by subsequent High Courts overturning their own precedents.

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Local government and the territories

Below the state level, local governments — city councils, shire councils, and municipal councils — provide services such as local roads, waste collection, libraries, parks and recreation facilities, and local planning approvals. Local government is not mentioned in the Australian Constitution; it is created by and derives its powers from state legislation. Each state parliament may establish, abolish, or alter local government areas and functions. The Australian Capital Territory and the Northern Territory occupy a different constitutional position from the states. Both are self-governing territories with their own legislative assemblies, but the Commonwealth Parliament retains the power under section 122 of the Constitution to override territory laws. In practice, this power is used sparingly and with respect for territory self-government. The territories participate in intergovernmental forums alongside the states but do not have the same constitutional protections.

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Reforming the division of powers

Changing the division of powers between the Commonwealth and the states requires a constitutional amendment under section 128 of the Constitution. The amendment must be passed by an absolute majority of both houses of the Commonwealth Parliament — or by one house twice in certain circumstances — and then approved at a referendum by a double majority: a national majority of voters, and a majority of voters in a majority of states (at least four of the six states). This high threshold makes constitutional change difficult, and only 8 out of 45 referendums have succeeded since federation. As a result, most shifts in the federal balance have occurred through High Court interpretation, intergovernmental agreements, and the Commonwealth's use of its financial powers rather than through formal constitutional amendment. The tension between Commonwealth and state powers remains a dynamic and contested feature of Australian governance, with debates over health funding, school education, environmental regulation, and infrastructure frequently raising questions about which level of government should bear responsibility.

Common questions

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