Ms Gambaro is co-sponsoring the cross-party bill to amend the Marriage Act that will still be introduced into the Parliament next week, despite the Liberal Party voting down a free vote for ministers. FOI documents have revealed retiring Brisbane MP Teresa Gambaro ignored departmental advice to move into an electorate office with LNP links. Credit:Andrew Meares That decision means there will not be enough votes on the floor to pass the bill in this term of government. A majority of lower house MPs would have to vote in favour of bringing on a vote, meaning the prospect of rebel backbenchers crossing the floor is slim. But the member for Brisbane said she planned to take a stand it if came to it.

"Marriage is not a symbol of moral superiority; it is a simple statement of love and one that in my view should be available to all Australians regardless of their sexuality," Ms Gambaro said in a statement. Liberal MP Teresa Gambaro Credit:Glenn Hunt "As I have stated many times, it is not for government to tell people who they can love." The Liberal Party's first openly gay parliamentarian, Dean Smith, on Wednesday became the first government member to declare their intention to cross the floor. "I intend to use the full liberties available to me as a government backbench senator to support same-sex marriage if a private member's bill comes before the Senate," Senator Smith said.

Queensland backbencher Wyatt Roy has also confirmed he will cross the floor if a vote is held. Ms Gambaro praised their political courage. "I commend the statements made by my Liberal Party parliamentary colleagues Warren Entsch, Wyatt Roy and Senator Dean Smith and confirm that, in accordance with the great traditions and principles of liberalism and individual choice upon which the Liberal Party was founded, I too intend to exercise the full liberties available to me as a Liberal backbencher and will cross the floor in support of the bill." It remained unclear when and how the government would decide whether or not to hold a referendum, which have a higher threshold for success and usually fail, or a plebiscite. Labor Deputy Leader Tanya Plibersek said the government was in chaos over the issue.

"Overnight we've heard the government again in chaos; we've heard some government ministers saying there should be a plebiscite, some saying there should be a referendum," she told reporters on her way into Parliament. In 2013, the Australian Electoral Commission estimated it would cost $121 million to hold a referendum on constitutional recognition of local government. This did not include federal funding for both sides to develop an information campaign. "This is an expensive and unnecessary delaying tactic for something we know the Australian people want," Ms Plibersek said. "We know that the people who are pushing for a referendum in the Liberal Party are opponents of marriage equality. They're doing it because they want to delay and hopefully prevent marriage equality ever becoming a reality." Labor says it would introduce legislation to recognise same-sex marriages within its first 100 days of office.