Supporters of making same-sex marriage legal are engaged in a parliamentary stand-off as the Turnbull government addresses an internal argument over funding the yes and no campaigns for a planned plebiscite.
Labor leader Bill Shorten and a group of crossbench MPs separately introduced identical bills to legalise gay marriage.
"We don't mind who gets the credit," Mr Shorten said, offering to work with the crossbench and coalition MPs on legislation.
"What will stand for all time is this parliament's statement that marriage is about love not about gender."
Greens MP Adam Bandt and independent Andrew Wilkie wrote to Labor last week about a joint legislative effort but didn't hear anything back from the opposition.
"I don't care whether marriage equality is owned by the government or the opposition or the crossbench, I just want the outcome," Mr Wilkie said.
With legislation now before parliament, it would take just three government MPs crossing the floor to force a vote on the issue, he said.
However, that's unlikely to happen with even strong supporters of same-sex marriage within coalition ranks now locked in behind the plebiscite.
Cabinet today is expected to settle on how the plebiscite would run, including how much, if any, taxpayer money should be given to the yes and no campaigns.
It is being asked to consider a February 11, 2017 vote, according to reports.
Conservative government MPs argue holding a plebiscite without funding the campaigns would go against what the coalition partyroom envisaged.
Liberal senator Eric Abetz warned cabinet not to "steamroll" the partyroom on the matter.
But one of the coalition's strongest advocates for change says it is unnecessary because there has already been much lobbying and debate on the issue.
"You'd have to be living on another planet not to already ... have your own opinion on this," Liberal MP Warren Entsch told ABC radio.
His private bill was the catalyst for the partyroom debate and he says that didn't include any discussion about public funding or even what form the national vote should take.
Senior figures in Australia's Anglican and Catholic churches claim the prime minister has promised them funding.
But Malcolm Turnbull insists he's only ever said if money was made available it would be given equally to both the yes and no campaigns.
Labor frontbencher Terri Butler hit out at conservative MPs pushing for public funding.
"These guys are all for fiscal discipline until they ... want public money to be given to oppose marriage equality," she told reporters.
Liberal backbencher James Paterson, who supports gay marriage, said neither side should be given taxpayer funds for their campaigns.
"If we can't think of a better way to spend taxpayers' money ... we're not doing our jobs," he told parliament.