In December 2017 amendments were carried out to The Marriage Act of 1961 so that the definition of marriage now reads “the union of two people to the exclusion of all others, voluntarily entered into for life”.
Since the amendments, same sex married parties have been able to apply for divorce in exactly the same manner as heterosexual couples i.e. they must demonstrate they have been separated for at least 12 months with no reasonable prospect of a reconciliation.
Same sex couples who legitimately married overseas prior to the 2017 Australian amendment can consider the 12 months separation period as beginning before December 2017, so long as they were married at that time and there has not been a period of reconciliation of more than three months.