Australia electoral system

After much experimentation and change over the past 150 years, Australia has found electoral arrangements that are accepted by Australia’s people, political parties, and parliamentarians.

The Australian electorate has experienced three types of voting systems: first past the post, preferential voting and proportional representation (single transferable vote). First past the post (a plurality system where the winner is the candidate with the most number of votes, though not necessarily an absolute majority of votes) was used for the first Australian parliamentary elections held in 1843 for the New South Wales Legislative Council and for most colonial elections during the second half of the 19th century. Since then there have been alterations to the various electoral systems in use around the country.

Today, two variants of preferential voting and two variants of proportional representation are used for all Australian parliamentary elections. Preferential voting is a majority system which attempts to ensure that a candidate secures an absolute majority of votes. Proportional representation systems are designed to allocate parliamentary seats to parties in proportion to their overall vote. These systems are explained in detail below.


Australia has a federal system of government with a national parliament and legislative assemblies and councils (parliaments) in each state and territory (there is no Legislative Council in Queensland, the Northern Territory, the ACT or Norfolk Island). Under the Constitution the federal government has responsibility for foreign relations, trade, defence and immigration. State government responsibilities include justice, consumer affairs, health, education, forestry, public transport and main roads. A variety of electoral systems are used for these parliaments. These are summarised in the table below.

Election Parliamentary chamber Seats Term Frequency Electoral system
Commonwealth House of Representatives 150 3 years 3 years Preferential voting–full allocation of preferences
Senate 76 6 years 3 years Proportional representation—‘Senate’ model
New South Wales Legislative Assembly 93 4 years 4 years Preferential voting–optional allocation of preferences
Legislative Council 42 8 years 4 years Proportional representation
Victoria Legislative Assembly 88 4 years 4 years Preferential voting – full allocation of preferences
Legislative Council 40 4 years 4 years Proportional representation — ‘Senate’ model
Queensland Legislative Assembly 89 3 years 3 years Preferential voting—optional allocation of preferences
Western Australia Legislative Assembly 57 4 years 4 years Preferential voting–full allocation of preferences
Legislative Council 34 4 years 4 years Proportional representation—‘Senate’ model
South Australia House of Assembly 47 4 years 4 years Preferential voting–full allocation of preferences
Legislative Council 22 8 years 4 years Proportional representation—‘Senate’ model
Tasmania House of Assembly 25 4 years 4 years Proportional Representation—Hare-Clark model
Legislative Council 15 6 years Annual Preferential voting–optional (partial) allocation of preferences
Northern Territory Legislative Assembly 25 4 years 4 years Preferential voting – full allocation of preferences
Australian Capital Territory Legislative Assembly 17 4 years 4 years Proportional representation — Hare-Clark model

The supreme law-making institution in Australia—the federal Parliament—has two houses: the House of Representatives and the Senate. Members of the House of Representatives seek re-election each time there is a federal election. The House of Representatives currently has 150 members elected by preferential voting. Proportional representation is used in the Senate.

For federal elections, the country is divided into electoral divisions. Australian voters choose among the candidates who are standing in their local division. As in other democracies, the cost of election campaigns and the source of funds for political activity are subject to public scrutiny. Since 1984, a system of public funding and disclosure for campaigns has been in place. Parties must receive at least four per cent of the vote in the elections to receive public funding administered by the Australian Electoral Commission. Compulsory voting in Australia maximises voter turnout and improves the quantum of campaign costs being reimbursed.
Parties must disclose total receipts and expenditure annually and sources of receipts above a specified threshold ($10,500 for 2007-0. Donors to political parties and ‘third parties’ also make disclosures.

Candidates and donors to candidates must also disclose donations above the same threshold and expenditure following each election.

A key feature of Australian democracy is that parties offer packages of policies for government and these are tested frequently at elections. Parliament expires three years after its first meeting, while an election can be held up to a couple of months after the expiration. In practice, general elections are held when the Governor-General agrees to a request from the Prime Minister, who canpick the occasion to begin a campaign.Since the first Parliament opened on 9 May 1901, the average life of parliaments has been about two and a half years.
Compulsory voting

Voting is compulsory both at federal elections and at elections for the state and territory legislatures. In some states, voting at municipal elections is also compulsory. On average about 5 per cent of enrolled voters fail to vote but prosecutions are rare and the fine, $20, is modest. In recent federal elections, with a voter turnout of approximately 95 per cent, informal voting—blank or not properly completed ballots—has accounted for about 5 per cent of all the votes cast.

Secret ballot

Australia pioneered reforms that underpin the electoral practices of modern democracies. One of these was the introduction of the secret ballot in 1855 by Victoria, which became known throughout the world as the ‘Australian ballot’.

Preferential voting

Preferential voting has become the accepted system in the federal and state parliaments of Australia and is used in municipal elections, political party elections, trade union elections, church elections, elections to company boards, voluntary bodies and sports clubs. Under this system, voters number the candidates on the ballot paper in the order of their preference.

In Australia there are two variants of this system: ‘full’ preferential voting, used for the House of Representatives at the federal level and the lower houses in Victoria, South Australia, Western Australia and the Northern Territory; and ‘optional’ preferential voting, used for the lower houses in New South Wales and Queensland. A partial ‘optional’ preferential voting system is used for Tasmania’s Legislative Council.

Under ‘full’ preferential voting each candidate must be given a preference by the voter. First, all the number ‘1’ votes are counted for each candidate. If a candidate gets more than 50 per cent (an absolute majority, 50 per cent plus one) of the formal first preference votes, the candidate is immediately elected. If no candidate has an absolute majority, the candidate with the fewest votes is excluded. These votes are then transferred to the other candidates according to the second preferences shown by voters on the ballot papers. If still no candidate has an absolute majority, again the remaining candidate with the fewest votes is excluded and these votes are transferred. This process will continue until one candidate has more than half the total votes cast and is declared elected.

Full preferential voting has been used in Australian federal elections since 1918. Under this system, voters rank candidates in order of preference on ballot papers. With ‘optional’ preferential voting the voter may allocate preferences to as few as one candidate. This system can produce similar outcomes to ‘full’ preferential voting but can also produce results where the winning candidate wins with less than half of the votes. It also clearly lessens the importance of preferences in many seats.

To help supporters order their preferences, political parties hand out how-to-vote cards at polling booths. The preferences that flow from less popular candidates often decide who wins. Distributing preferences after election day can take days or even weeks.

Proportional representation (single transferable vote)

Proportional representation systems were devised to produce ‘proportional’ election results—parties should win parliamentary seats roughly in proportion to the size of their vote. Ideally, 50 per cent of the vote should win about 50 per cent of the seats. Proportional representation is not a single method of election, for there are a number of variations in use, including the single transferable vote, which is a preferential voting system designed to ensure that votes are for individual candidates rather than for party lists. The two variants of this used in Australia: the ‘Senate’ model and the Hare-Clark system.

The ‘Senate’ model elections increases the chances of minor parties and independents winning seats compared to the single member constituency system used for the House of Representatives. It produces closer results in the struggle between the major parties and makes it difficult for a major party to gain control of the Senate and in the upper houses of New South Wales, Victoria, South Australia and Western Australia where it is used.

The Hare-Clark version of proportional representation is used for elections for the Tasmanian House of Assembly and the Australian Capital Territory Legislative Assembly. This system ensures that no seat is safe, creates an electoral system where party members fight each other as much as their external opponents and operates in such a way that minority governments are more common than when preferential voting is used.

Key facts

  • Australian elections are conducted in secret using paper ballots (lists of candidates)
  • Our electoral system utilises both preferential voting and proportional representation
  • The cost of election campaigns and the source of funds for political activity are subject to close public scrutiny

Further information

last updated May 2008