Australia is a representative democracy, which means that Australians vote to elect members of parliament to make laws and decisions on their behalf. It is compulsory for Australian citizens 18 years and over to enrol to vote. It is also compulsory to attend a voting place on Election Day, or to vote by mail.
At federal elections, Australians choose members of parliament to represent their views and interests, in the House of Representatives and the Senate. In this way, federal Parliament serves Australians and is accountable to them.
Electing members of the House of Representatives
Section 28 of the Australian Constitution states that House of Representatives elections must be held at least every three years. The Prime Minister decides the date for an election. This could be at any time during the three-year term.
There are 150 members elected to the House of Representatives—one for each of Australia's 150 electorates. An average of 150 000 citizens live in each electorate, with an average of 94 000 voters.
Each member is elected using a system of preferential voting, designed to elect a single member with an absolute majority for each electorate. Using this system, voters write a number in the box beside every name on the ballot-paper; '1' for their first preference, '2' for their second preference and so on, until all the boxes are numbered. If a candidate gains an absolute majority (more than half) of first preference votes, they win the seat. If no candidate receives an absolute majority, the candidate with the least number of votes is excluded and their votes are redistributed according to second preferences. The process of redistributing votes according to preferences continues until one candidate receives more than 50% of the vote and is then elected.
Twelve senators are elected to represent each state and two senators are elected to represent each territory. State senators are elected for a period of six years using a system of rotation that ensures that only half the state senators end their term every three years. Territory senators are elected for a period of three years at the same time as the members of the House of Representatives and half of the Senate.
Half-Senate elections are usually held at the same time as House of Representatives elections, though they do not have to be.
Senators are elected using a system of proportional voting, designed to allocate seats to candidates in proportion to votes cast in an election. Proportional voting allows for a wider range of political parties and/or Independents to be elected to the Senate. Using this system, voters have a choice of voting above-the-line or below-the-line:
- Above-the-line voting requires voters to put a number '1' in the box next to the party or group they choose. This party or group has already registered its preferences with the Australian Electoral Commission and defined how preferences are to be distributed. These preferences are then distributed for the voter.
- below-the-line voting requires voters to write a number in the box beside every name on the ballot-paper; '1' for their first preference, '2' for their second preference and so on, until all the boxes are numbered.
To win a seat, a senator must win a quota of first and later preferences. For a state senator at a half-Senate election, this equals 14.3% of the total state vote, while a territory senator must win 33.3% of the total territory vote. The counting procedure for a Senate election is more complicated than the system used for the House of Representatives—it sometimes takes several weeks after an election to count all the Senate votes and finalise the result.
Finalising the result
Once the election result is finalised, the successful candidates are announced and the official election documents, called writs, are returned to the Governor-General or state governors.
By-elections and casual vacancies
A by-election is a mini-election held for a House of Representatives electorate if a member resigns or dies between federal elections.
A casual vacancy occurs in the Senate if a senator resigns or dies before their term of office has expired. They are replaced by a candidate from the same political party, chosen by the parliament or legislative assembly of that state/territory.
Federal elections are organised and run by the AEC, who make sure that elections are free, fair and legal. The Commonwealth Electoral Act 1918 and the Australian Constitution set out the requirements for running elections.