Hi Barry. Thanks for your question. There have been a number of changes to our electoral system since federation. These include the introduction of compulsory voting, the lowering of the voting age and various changes to the way voting is conducted for the House of Representatives and the Senate.
Federal elections are organised and run by the Australian Electoral Commission 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.
Further changes to our system can be made by alterations to the Commonwealth Electoral Act. These changes would need to be agreed to by a majority vote in the House of Representatives and the Senate and given Royal Assent by the Governor General. This happened recently when the Commonwealth Electoral Amendment Bill 2016 was passed by the Parliament changing the way voters elect senators.
More information on elections and the electoral system can be found in the House of Representatives Practice.