Same-sex marriage is one step closer to being achieved as the ALP says yes to a bill for gay marriage.

In a historic move, the ALP national conference voted to adopt gay marriage in its official party platform.

But delegates also voted to allow MPs a conscience vote on legislation, which could mean the defeat of any marriage equality bill introduced to parliament.

Greens Senator Sarah Hanson Young said the party wants to co-sponsor a same-sex marriage bill to present to parliament in the new year, and Labor backbencher Stephen Jones has pledged to introduce a private members bill.

Coalition leader Tony Abbott has ruled out a conscience vote for his frontbench MPs on this issue, but a recent Galaxy poll showed 80 per cent of respondents, including 76 per cent of Coalition voters, want him to change his position.

Former Liberal leader Malcolm Turnbull, whose NSW seat of Wentworth has a high GLBTI population, has also called on Abbott to allow a conscience vote for all MPs, indicating some of his party’s members would cross the floor.

Australian Marriage Equality national convenor Alex Greenwich said: “We hope that Mr Abbott will recognise that the momentum for marriage equality is unstoppable and by granting a conscience vote he will allow the coalition to play a part in this historic reform.”

Prior to the conference, GetUp! Released a YouTube clip of two men falling in love that gathered more than 3 million views in a few days. The group also presented a pro-equality petition to Gillard signed by more than 140,000 Australians and a record 12,000 marched in Sydney on the day of the vote.