The Constitution of Australia — Overview

Introduction

The Constitution of Australia is the supreme law of the Commonwealth of Australia. It is contained in the Commonwealth of Australia Constitution Act 1900 (Imp), a statute of the Parliament of the United Kingdom, which received royal assent on 9 July 1900 and came into force on 1 January 1901. The Constitution establishes the framework of the federal Commonwealth government, distributes powers between the Commonwealth and the six original States, and provides for the structure and operation of the three branches of government: the Parliament (Chapter I), the Executive Government (Chapter II), and the Judicature (Chapter III). As a rigid constitution, it can only be amended by a referendum under s 128, requiring a double majority of electors nationwide and a majority of electors in a majority of States.

The Federal Compact

The Constitution embodies a federal compact between the six self-governing British colonies — New South Wales, Victoria, Queensland, South Australia, Western Australia, and Tasmania — which agreed to unite in an “indissoluble Federal Commonwealth.” The federal structure was the product of a series of Constitutional Conventions held during the 1890s, culminating in the Australasian Federal Convention of 1897–1898, which drafted the Constitution. The draft was approved by referendums in each colony and enacted by the Imperial Parliament. The federal nature of the Constitution is expressed through the division of legislative powers between the Commonwealth and the States, the representation of the States in the Senate, and the reservation of residual powers to the States.

Structure and Content

The Constitution is divided into eight chapters. Chapter I (ss 1–60) establishes the Parliament as a bicameral legislature comprising the Queen (represented by the Governor-General), the Senate, and the House of Representatives. It sets out the composition, powers, and procedures of both houses, including the double dissolution mechanism under s 57 for resolving deadlocks between the houses.

Chapter II (ss 61–70) vests the executive power of the Commonwealth in the Queen, exercisable by the Governor-General as her representative. It establishes the Federal Executive Council and provides for the appointment of Ministers of State, who must be members of Parliament (or become members within three months). This reflects the Westminster system of responsible government, whereby the Executive is drawn from and accountable to the Parliament.

Chapter III (ss 71–80) establishes the Judicature, vesting the judicial power of the Commonwealth in the High Court of Australia, such other federal courts as Parliament creates, and state courts invested with federal jurisdiction. Chapter III enshrines the separation of powers by confining judicial power to Chapter III courts and guaranteeing their independence.

Chapter IV (ss 81–105A) deals with Finance and Trade, including the Consolidated Revenue Fund, the requirement that appropriations be authorised by law, and the controversial s 96, which empowers the Commonwealth to grant financial assistance to any State “on such terms and conditions as the Parliament thinks fit.” Section 92 guarantees interstate trade and commerce “absolutely free.”

Chapter V (ss 106–120) preserves the State Constitutions and the powers of the State Parliaments, subject to the Commonwealth Constitution. Chapter VI (s 121) deals with the admission of new States. Chapter VII (ss 122–126) contains miscellaneous provisions, including s 122, which confers plenary power over the Territories. Chapter VIII (s 128) sets out the amendment procedure.

The Washington Synthesis

The Australian Constitution is often described as a “Washington synthesis” — a combination of the Westminster system of responsible government (derived from the United Kingdom) with American-style federalism and a written, rigid constitution. Unlike the United Kingdom’s unwritten constitution, Australia’s Constitution is codified and judicially enforceable. Unlike the United States model, however, Australia retained the Crown as the formal head of state and maintained the principle that Ministers must sit in Parliament. This synthesis has generated distinctive features of Australian constitutional law, including the implied freedom of political communication, the Melbourne Corporation principle of state immunity, and the unique interaction between responsible government and federal judicial review.

The Crown and the Governor-General

The Constitution identifies the Queen (now Queen Elizabeth II, succeeded by King Charles III) as the formal head of state. In practice, the Queen’s constitutional functions are exercised by the Governor-General, who is appointed on the advice of the Prime Minister. The Governor-General exercises a range of powers, including assenting to bills, appointing and dismissing Ministers, commanding the defence forces, and dissolving the Parliament. While most of these powers are exercised on the advice of Ministers, the Governor-General retains certain reserve powers, including the power to dismiss a Prime Minister who has lost the confidence of the House of Representatives — a power controversially exercised by Sir John Kerr in 1975.

The Amendment Procedure

Section 128 provides a rigid amendment procedure: a proposed law to alter the Constitution must be passed by an absolute majority of both Houses of Parliament (or by one House twice if the Houses disagree) and then submitted to a referendum. The referendum requires a double majority: a majority of all electors voting nationwide, and a majority of electors in a majority of States (four out of six). Since 1901, only 8 of 44 referendums have been successful, including the 1967 Aboriginals referendum (90.8% yes) and the 1977 Senate elections referendum. The high failure rate reflects the deliberate difficulty of the amendment process and the conservative voting patterns of the Australian electorate.

The Statute of Westminster and the Australia Acts

The Constitution originally functioned within the framework of the British Empire. The Statute of Westminster 1931 (Imp) removed the UK Parliament’s power to legislate for the Commonwealth without its request and consent, and was adopted by Australia in 1942 (retrospectively to 1939). However, the States remained subject to Imperial legislative power until the Australia Acts 1986, which simultaneously terminated the UK Parliament’s power to legislate for Australia (including the States), abolished all appeals to the Judicial Committee of the Privy Council, and confirmed the complete legislative independence of both Commonwealth and State Parliaments. The Australia Acts 1986 represent the final severance of Australia’s constitutional ties with the United Kingdom.

Constitutional Conventions

Alongside the written text, Australian constitutional law is shaped by a body of constitutional conventions — unwritten rules of political practice that are considered binding by those who operate the Constitution. Key conventions include the requirement that the Governor-General act on the advice of Ministers, the appointment of the Prime Minister as the parliamentary leader who commands a majority in the House of Representatives, and the principle of collective ministerial responsibility. These conventions are not legally enforceable by the courts but are fundamental to the operation of responsible government. The 1975 constitutional crisis, in which the Governor-General dismissed Prime Minister Gough Whitlam, highlighted the tension between constitutional text and convention, and remains the subject of ongoing scholarly debate.