Electoral Systems of The Australian States and Territories - South Australia

South Australia

The 47-member South Australian House of Assembly is elected under the preferential Instant-runoff voting (IRV) system. If on the count of primary or first preference votes (votes marked with the number '1'), no candidate achieves more than 50% of the vote, the candidate with the fewest votes is excluded and their votes distributed according to the next available preferences, their 2nd or third choice candidate. This process of exclusion continues until one candidate achieves 50% of the vote.

The 22-member South Australian Legislative Council is elected under the preferential Single Transferable Vote (STV) system through a means of Group voting tickets. Voters can choose to vote for a ticket by placing the number '1' in one of the ticket boxes "above the line" or can vote for individual candidates by numbering all the boxes "below the line" (54 in the 2006 election). In above the line voting, ticket votes are distributed according to the party or group voting ticket registered before the election with the election management body. As most ballot papers are above the line, this form of voting often leads to pre-election trading between parties on how each party will allocate later preferences to other parties and candidates.

The independent State Electoral Office, which conducts elections, is responsible for a mandatory redistribution of House of Assembly boundaries before each election to ensure one vote one value.

Like all other states and territories voting in South Australia is compulsory, however unlike other states initial enrolment is not compulsory so a voter could theoretically not be compelled to vote if they chose never to enrol.

Turnout rates are above 90%. Informal voting, which occurs when a voting slip is not valid, is at a rate of under 5%. Voting slips are informal when they are not filled out correctly, such examples are not numbering subsequent numbers, not filling out all the candidate boxes with numbers (except the last candidate), or in some other way that is verified by the State Electoral Office as illegible. South Australian elections have some features that are unique to the rest of Australia.

Parliaments have fixed four-year terms. The Electoral Act stipulates that the election campaign must run for a minimum of 25 days or a maximum of 55 days.