Australian Greens leader Bob Brown says he expects Prime Minister Julia Gillard and the ALP to back same-sex marriage at its national conference.
Every state and territory Labor branch, except NSW, have passed motions supporting same-sex marriage, and the issue is expecting to come before the party's national conference in December. Senator Brown said he expected the party to change its platform.
"It is becoming a milestone as far as the Labor Party," he told reporters in Hobart on Friday.
"You've only got to look at the state conferences and the territory conferences to know they're going to support it.
"Under those circumstances, I think we'll find Prime Minister Gillard joining the incoming tide to fix up the marriage laws and allow equal marriage rights to people regardless of their sexuality."
Senator Brown also backed moves from his Tasmanian counterpart Nick McKim to legislate for same-sex marriage.
The state's lower house this week became the first Australian house of parliament to move a motion supporting marriage equality.
Mr McKim, who introduced the motion, said he would bring legislation before the state parliament to legalise marriage if the federal government did not act on the issue "in a timely way".
Premier Lara Giddings, who voted in favour of the motion, said she had legal advice that indicated it was a Commonwealth issue.
But Senator Brown said it was at least worth testing the waters. "I think the states have the power to do that.
The one way to ensure that's sorted out is by legislating," he said. "You don't say at the outset, as Ms Giddings is doing, 'Oh, there might be a question about it, so we won't do it, even though it's the right thing'. "You go ahead and do it. Let someone challenge it if they want to."
