Tasmania's bid to be first state to legalise same sex marriage is facing its toughest test in the state's upper house, where an advocate is calling for change though it may end up in the High Court.
After its passage through the House of Assembly, Ruth Forrest brought the bill into the state's Legislative Council this afternoon with a call to embrace it.
"If we avoid the opportunity for reform because of the prospect of a High Court challenge, we would miss many prospects for reform," Ms Forrest told the council. "This is social reform that matters so much to so many Tasmanians."
Ms Forrest said it was generally agreed that the states' power to legislate in marriage was a legal grey area, but it was equally clear that the Commonwealth did not have a monopoly on leadership.
Tasmania, the last state to decriminalise gay sex, now had a chance to guide the nation, she said.
Observers say the mainly independent 15 member Legislative Council is almost evenly split over the bill, which is expected to be voted upon tomorrow.
The council's president, Sue Smith, said she would vote against the bill if required to give a casting vote.