Protesters march in Melbourne for gay marriage rights.

Protesters march in Melbourne for gay marriage rights. Photo: Craig Sillitoe

The vote on gay marriage has been brought forward from the end of the year and could be held as early as August following concerns from Labor's Right that the debate is damaging the party.

It is accepted on all sides that the push to legalise gay marriage will be defeated.

According to sources, in this morning's caucus meeting the government whip Joel Fitzgibbon said that due to the desire of some within Labor to "hasten the process", more time would be allotted for the debate, meaning the vote could be held earlier. Because the bill, sponsored by Labor's Stephen Jones, is a private member's bill, there is only limited time for debate on Mondays.

Without extra time allotted, there would have been no final vote until the end of the year at the earliest.

Greens MP Adam Bandt has his own separate bill and will delay a vote on that until later this year or early next year in the hope public pressure changes minds.

"It should be done not just because it's popular but because it is right," he said.

"But I'm optimistic of achieving reform within the life of this Parliament, with some more discussion and more persuasion."

The Finance Minister, Penny Wong, one of the strongest proponents for a change to the Marriage Act, said yesterday that change would eventually come.

"I think the campaign is not going to go away because ultimately it's a campaign for people's equality," she said.

A seven-member parliamentary committee split 4-2 against same-sex marriage yesterday with one abstention as it handed down a report that contained no recommendations, only information for all politicians to use to inform their final decision.

The Prime Minister, Julia Gillard, will vote against gay marriage but has allowed Labor MPs a conscience vote.

Number-crunchers estimate about 36 of the 70 Labor MPs will vote for same-sex marriage, while 10 to 15 are undecided and the rest will vote against.

Tony Abbott will not allow a conscience vote and all Coalition MPs are bound to vote against same-sex marriage. Backbenchers can cross the floor but any frontbencher who does so would have to resign from the shadow ministry. Malcolm Turnbull said he would like to support the bill but it would cost him his job.

Parliament's standing committee on social policy and legal affairs received a record 276,437 responses to an online survey it conducted as part of its inquiry.

The committee chairman, Labor MP Graham Perrett, along with fellow Labor MP Laura Smyth, came out in favour of gay marriage. Liberal MPs Sharman Stone and Ross Vasta and Labor's Mike Symon and Shayne Neumann were opposed. The other member, Liberal moderate Judi Moylan, gave no separate opinion.

Church groups and the Australian Christian Lobby have fiercely campaigned against gay marriage, despite Labor's bill exonerating the churches and any other religious groups from having to marry gay people.

Mr Perrett, who holds a marginal Queensland seat, said ''it is important to remember that God did not write the Marriage Act. It is written by lawyers and legislators and must reflect the views and values of today."

With public opinion polls consistently showing majority support for same-sex marriage, Mr Perrett said it was incumbent upon MPs to respond to growing public support "by categorically opposing laws that legitimise discrimination".

Ms Stone and Mr Vasta said the Liberals had promised before the federal election not to legalise gay marriage. 

''I do not accept that the view towards marriage has changed since the 2010 federal election,'' Ms Stone added.

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