Twenty-two members of the state's lower house passed the ammendment to the Relationships Act, with only three members - Liberals Rene Hidding, Michael Ferguson and Jacqui Petrusma - voting against it.
Attorney-General Lara Giddings reportedly told the the ABC, the changes will remove discrimination for same-sex couples in registered relationships.
"This is really a small step, but a significant and important step for those people who have registered or been through a civil union process elsewhere around the world and want us to recognise that relationship as indeed being in existence," she said.
Liberal MP Michael Ferguson, who voted against the bill, reportedly told the ABC that the legislations is a political tool to get same-sex marriage legalised.
Ms Giddings reportedly denied that legalising gay marriage was the Government's 'next step'.
