The short answer

a referendum changes—and what it does not

A federal referendum can approve a proposed constitutional alteration through the required voting majorities. Section 128 of the Australian Constitution sets out the process: a proposed amendment must first be passed by an absolute majority of both Houses of Parliament, then submitted to Australian electors at a referendum held between two and six months later. To succeed, the proposal must achieve a double majority: a national majority of voters across Australia, and a majority of voters in a majority of the states (at least four of the six). If the referendum passes, the Governor-General gives royal assent to the amending law and the Constitution is formally altered. A referendum does not automatically enact policy detail, create funding programs, establish administrative structures or change ordinary legislation. It only alters the text of the Constitution itself. Any subsequent laws, institutions or programs that the amendment enables must still be passed through the ordinary legislative process by Parliament. Since Federation, only eight of 44 referendum proposals have succeeded, reflecting the deliberately high threshold set by section 128.

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.

Evidence review

The constitutional basis: section 128

Section 128 of the Australian Constitution is the sole mechanism for altering the Constitution. It provides that a proposed law to alter the Constitution must be passed by an absolute majority of both Houses of the Commonwealth Parliament. An absolute majority means more than half of the total number of members of each House, not just more than half of those present and voting.

Once passed by Parliament, the proposed amendment must be submitted to a referendum of Australian electors no sooner than two months and no later than six months after parliamentary passage. This waiting period ensures electors have adequate time to consider the proposal. In certain circumstances, if one House passes a proposal twice and the other House rejects it twice, the Governor-General may submit the proposal directly to electors, bypassing the deadlocked House.

Voting in referendums is compulsory for all enrolled electors, just as it is for federal elections. Electors write either 'Yes' or 'No' in the box opposite each question on the ballot paper. The rules governing referendum procedures are set out in the Referendum (Machinery Provisions) Act 1984, administered by the Australian Electoral Commission.

Evidence review

The double majority requirement

To succeed, a referendum proposal must achieve a double majority. First, it must win a national majority: more than half of all voters across Australia, counting electors in both the states and territories, must vote 'Yes'. Second, it must win a majority of electors in a majority of the states: more than half the voters in at least four of the six states must vote 'Yes'.

This double majority requirement is deliberately difficult to meet. It was designed by the framers of the Constitution to ensure that any alteration has widespread support across the country and cannot be imposed by the more populous eastern states alone. Votes in the territories (the Australian Capital Territory and the Northern Territory) count towards the national majority but not towards the state majority count. Since Federation in 1901, only eight out of 44 referendum proposals have been approved. The last successful referendum before 2023 was in 1977, a gap of 46 years.

Evidence review

What a successful referendum actually changes

A successful referendum alters the text of the Australian Constitution itself. The approved amendment becomes part of the supreme law of the land, binding on all Parliaments, governments and courts in Australia. The change is formally made when the Governor-General gives royal assent to the bill that was approved at the referendum.

The nature of the change depends entirely on the wording of the proposed amendment. Some amendments have transferred specific legislative powers from the states to the Commonwealth, such as the 1946 referendum that gave the Commonwealth power over social services. Others have made structural changes to the system of government, such as the 1977 referendum that set a retirement age of 70 for High Court judges. Some have addressed democratic participation, such as the 1967 referendum that removed the exclusion of Aboriginal people from the census and gave the Commonwealth power to make laws for them.

Evidence review

What a referendum does not change

A referendum only changes the Constitution. It does not automatically enact any policy detail, create government programs, allocate funding, establish administrative bodies or change ordinary legislation. Any practical measures that the constitutional change enables must still be passed by Parliament through the ordinary legislative process, including introduction as a bill, debate in both Houses and royal assent.

This distinction is often misunderstood. If a referendum gave the Commonwealth Parliament a new legislative power, for example, the Parliament would still need to pass an Act using that power before any practical change occurred. The content of that Act would be subject to the usual parliamentary and committee scrutiny, and could be amended or repealed by a future Parliament. The referendum result itself creates the constitutional permission for Parliament to act, not the action itself.

Similarly, a referendum cannot override the High Court's role in interpreting the Constitution. After any amendment, it remains open to the High Court to determine the scope and meaning of the new or altered provision, just as it interprets all constitutional provisions. The practical effect of a referendum may therefore be shaped by subsequent judicial interpretation.

Evidence review

The information campaign: Yes and No cases

In the four weeks after Parliament passes a referendum proposal, members and senators who voted for the proposal prepare a 'Yes' case and those who voted against prepare a 'No' case. These are submitted to the Australian Electoral Commissioner. If the proposal was passed unanimously by Parliament, no 'No' case is prepared.

The Electoral Commissioner has the Yes and No cases printed together with a statement showing the proposed constitutional alterations. This pamphlet must be posted to every enrolled elector, as nearly as practicable, no later than 14 days before polling day. The pamphlet is designed to ensure that every voter receives official information about what they are being asked to decide, presented from both perspectives. The AEC also provides general information about the referendum process but has no role in advocating for either side. The substantive campaign for and against the proposal is conducted by political parties, community organisations and individuals, and is regulated by laws on electoral funding and authorisation.

Common questions

Before you rely on the answer

Why have so few referendums been successful in Australia?

The double majority requirement in section 128 sets a very high bar. A proposal must win both a national majority and majorities in at least four of the six states. Many proposals have won a national majority but failed to carry enough states. Additionally, Australian voters have historically been cautious about constitutional change, often influenced by the principle of 'if you don't know, vote no'. Bipartisan support is widely regarded as essential; only one of the eight successful referendums (the 1967 Aboriginal peoples referendum) achieved success without both major parties actively supporting it.

Can the Constitution be changed without a referendum?

No. Section 128 is the only mechanism for altering the text of the Australian Constitution. There is no alternative process such as a constitutional convention or a vote of Parliament alone. However, the High Court's interpretation of the Constitution can change over time, effectively altering how constitutional provisions operate without changing the text. The Constitution can also be amended indirectly through the referral of state powers to the Commonwealth under section 51(xxxvii), which does not require a referendum but does require state parliament legislation.

What happens if a referendum question is unclear?

The wording of the referendum question is determined by the bill passed by Parliament, not by the AEC. If the question is ambiguous, voters must interpret it as best they can, aided by the Yes and No cases in the official pamphlet. There is no process for challenging the wording of a referendum question before the vote. After a successful referendum, the High Court may later be called upon to interpret the meaning of the amendment, which can resolve ambiguities but cannot undo the amendment itself.

Source spine

Primary material used for this guide

Review trigger: Amendment to section 128 of the Constitution changing the referendum process or thresholds; legislation altering the Referendum (Machinery Provisions) Act 1984 in a way that materially changes referendum procedures; High Court decision that alters the interpretation of section 128 or the double majority requirement; a successful referendum that creates new categories of constitutional alteration

Archive note: Written 2026-07-17 using the Australian Electoral Commission Referendums Overview page (updated 6 June 2011) and Infosheet 20 from the Parliament of Australia (updated March 2026). The article describes the referendum process as it existed at the time of writing. The last referendum considered was the 2023 Aboriginal and Torres Strait Islander Voice referendum.

Primary links are provided without affiliate or tracking parameters. Confirm that the source still applies to the bill, sitting date, jurisdiction or reporting period before relying on it.