排序複選制
In 1918, the 1902 Act was repealed and replaced by the "Commonwealth Electoral Act 1918". Many of the present features of the Australian electoral system were introduced after the 1918 Act came in force. Instant-runoff voting was introduced for the House of Representatives in 1918, compulsory voting was introduced in 1924, and the single transferable vote was introduced for the Senate in 1949. Indigenous Australians were granted the right to vote at federal elections in 1962. The qualifying voting age was lowered to 18 in 1973.