The politics of Australia has a mild two-party system, with two dominant political groupings in the Australian political system, the Australian Labor Party and the Liberal Party of Australia. Federally, 13 of the 150 members of the lower house (Members of Parliament, or MPs) are not members of major parties, as well as 20 of the 76 members of the upper house (senators).
The Parliament of Australia has a number of distinctive features including compulsory voting, with full-preference instant-runoff voting in single-member seats to elect the lower house, the Australian House of Representatives, and the use of the single transferable vote to elect the upper house, the Australian Senate.