Compulsory voting
Compulsory voting is an effect of laws which require eligible citizens to register and vote in elections, and may impose penalties on those who fail to do so. , 22 countries provide for compulsory voting, and 11 democracies — about 5% of all United Nations members — enforce it.
Electoral systems of the Australian states and territories
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.