Timing of constitutional referendums: a quick guide

13 June 2023

PDF version [512 KB]

Dr Damon Muller
Politics and Public Administration

As with a federal election, the timing of a constitutional referendum is regulated by both constitutional and legislative requirements. This Quick Guide outlines these requirements and how the electoral calendar relates to the Constitution Alteration (Aboriginal and Torres Strait Islander Voice) 2023 Bill.

Legislative requirements

The Constitution

A federal constitutional referendum requires Parliament to pass a constitution alteration Bill, provided for by section 128 of the Australian Constitution. A constitution alteration Bill does not gain Royal Assent until it is agreed to by a majority of voters in a majority of states at a referendum, so the timelines for a referendum are measured from the passage of the Bill through the Parliament, not from Assent to the Bill.

For a law that has passed through both Houses of Parliament, the Constitution requires that the proposed law be submitted to the voters ‘not less than two nor more than six months after its passage through both Houses’.[1]

The Referendum (Machinery Provisions) Act 1984:

Within 4 weeks of the Bill passing, the text of the Yes and No cases, authorised by a majority of parliamentarians who voted for and against the constitution alteration bill respectively, are to be forwarded to the Electoral Commissioner (paragraph 11(1)(b)).

The Electoral Commissioner must distribute the pamphlet containing the authorised cases for and against the change to the Constitution not later than 14 days before the voting day. In 1999 and 2013 (for the local government referendum that did not proceed), the Australian Electoral Commission (AEC) distributed instructions to parliamentarians on the formatting of the Yes and No cases, and it is likely that it will do so similarly for this referendum.

The writ’s timetable

The Governor-General issues the writ for a referendum, specifying:

  • The day for the close of the Rolls, which must be the 7th day after the issue of the writ (subsection 9(1))
  • The voting day, which must be a Saturday and between 33 days and 58 days after the issue of the writ (subsection 9(2))
  • The day for the return of the writ, which must be not more than 100 days after the issue of the writ (subsection 8(1A)).

As soon as practicable after the issue of the writ, voters who are registered as general postal voters must be sent a postal ballot paper (subsection 58(1)).[2] Postal vote applications may also be made after the issue of the writ (subsection 55(4)) but must be received at least 3 days before voting day (subsection 55(5)). Postal votes must be received within 13 days after voting day to be included in the count (paragraph 89A(1)(b)).

If the referendum is not being held in conjunction with a federal election, mobile polling may commence from 19 days before voting day (paragraph 51(5)(b)).

The earliest date for pre-poll voting is 12 days before voting day (paragraph 73AA(1AA)(b)). If the pre-poll office is a mobile voting location, it can commence 19 days before voting day (paragraph 73AA(1AA)(a)).

When can the Governor-General issue the writ?

In evidence to Senate Estimates on 23 May 2023, the AEC stated that the writ for a referendum cannot be issued before the minimum 2 months required by the Constitution had elapsed. This would mean that the referendum voting day cannot be sooner than 2 months plus 33 days after Parliament passed the Bill. In a 2013 letter published on its website, the AEC cited legal advice that distributing postal ballots for a referendum to general postal voters as soon as practicable after the issue of the writ, as required by section 58 of the Act for a referendum that is not being held at the same time as a general election, constituted submitting the proposed law to the voters.[3] The AEC has not provided any more detail in relation to this legal advice.

In each of the three referendums since the Act came into force (1984, 1988 and 1999), the writs for the referendum were issued between 7 and 11 days short of the 2 months since the Parliament passed of the constitution alteration Bills (see Table 1; in 1984 the referendum was held in conjunction with a federal election, which affects the timing requirements).

Table 1: Dates and details of referendums since 1984

Subject/Proposal Date Passed Parliament Passed both houses Date Issue of Writ Polling Day Held with election
Terms of Senators 4 Sep 84 Yes 26 Oct 84 1 Dec 84 Yes
Interchange of Powers 4 Sep 84 Yes 26 Oct 84 1 Dec 84 Yes
Parliamentary Terms 1 Jun 88 Yes 25 Jul 88 3 Sep 88 No
Fair Elections 1 Jun 88 Yes 25 Jul 88 3 Sep 88 No
Local Government 1 Jun 88 Yes 25 Jul 88 3 Sep 88 No
Rights and Freedoms 1 Jun 88 Yes 25 Jul 88 3 Sep 88 No
Republic 12 Aug 99 Yes 1 Oct 99 6 Nov 99 No
Preamble 12 Aug 99 Yes 1 Oct 99 6 Nov 99 No

Source: AEC and Parliamentary Handbook


When is the Voice referendum possible?

The June 2023 sitting period is the soonest opportunity for the Constitution Alteration (Aboriginal and Torres Strait Islander Voice) 2023 Bill (the Bill) to pass the Senate, and thus the Parliament (having already passed the House by an absolute majority). Passage by the end of the following sitting weeks would result in the key dates for a referendum as outlined in Table 2.

Table 2: Key referendum dates based on the final day of each sitting week

Last day of sitting week Two month minimum First Saturday 33 days later (first possible voting day) Last Saturday within six months (last possible date)
16 Jun 2023 16 Aug 2023 23 Sep 2023 9 Dec 2023
22 Jun 2023 22 Aug 2023 30 Sep 2023 16 Dec 2023

Source: Parliamentary Library calculations

While 14 October 2023 is reportedly the Government’s preferred referendum date, 7 October 2023 also a possibility. Either date would require the Bill passing the Senate during the June sitting weeks if the Government does not intend to change the sitting calendar. Passing the Bill in the August sitting period would allow the constitutionally required 2-month minimum period, but not the additional 33 days required under the Act.

Depending on whether the Bill passes during the first or second of the June sitting weeks, 23 or 30 September would also be viable voting days. However the AFL and NRL grand finals are scheduled for the weekend of 30 September and 1 October 2023, which makes that an unlikely option. The Western Australian local government elections are also scheduled for 21 October 2023. Following 14 October, the Parliament has sitting weeks scheduled for all but two weeks into early December, which if unchanged would make campaigning more difficult for parliamentarians.

A 7 October voting day requires the writ to be issued no sooner than 10 August (or as soon as two months has elapsed from the passage of the Bill, which may be as late as 16 August) and no later than 4 September 2023. A 14 October polling day would require the writ to be issued between 17 August (or two months after the passage of the Bill, which may be as late as 22 August) and no later than 11 September 2023.


[1].   The Acts Interpretation Act 1901 specifies that a period of 2 or more months is a period that ends immediately before the corresponding day of the calendar month that is that number of calendar months after the starting month (subsection 2G(2)). The Constitution also provides for a referendum where a constitution alteration Bill has not passed both Houses.

[2].   General postal voters are voters who meet certain requirements and who register to be automatically sent a postal ballot each election, rather than needing to fill out a postal vote application for each election.

[3].   This timing issue was stated by the AEC as the reason the local government referendum could not be held in conjunction with the 7 September 2013 federal election—the timing of the passage of the constitution alteration bill, in conjunction with the requirements of the Commonwealth Electoral Act 1918 for postal voting, meant the referendum could not be held in conjunction with a federal election any earlier than 14 September 2013.


For copyright reasons some linked items are only available to members of Parliament.

© Commonwealth of Australia

Creative commons logo

Creative Commons

With the exception of the Commonwealth Coat of Arms, and to the extent that copyright subsists in a third party, this publication, its logo and front page design are licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Australia licence.

In essence, you are free to copy and communicate this work in its current form for all non-commercial purposes, as long as you attribute the work to the author and abide by the other licence terms. The work cannot be adapted or modified in any way. Content from this publication should be attributed in the following way: Author(s), Title of publication, Series Name and No, Publisher, Date.

To the extent that copyright subsists in third party quotes it remains with the original owner and permission may be required to reuse the material.

Inquiries regarding the licence and any use of the publication are welcome to webmanager@aph.gov.au.

This work has been prepared to support the work of the Australian Parliament using information available at the time of production. The views expressed do not reflect an official position of the Parliamentary Library, nor do they constitute professional legal opinion.

Any concerns or complaints should be directed to the Parliamentary Librarian. Parliamentary Library staff are available to discuss the contents of publications with Senators and Members and their staff. To access this service, clients may contact the author or the Library‘s Central Entry Point for referral.