"The party policy to retain the definition of marriage as contained in the Marriage Act is supported by the majority of Liberal and National MPs and senators and I'd say many of them would hold the view that this is what our party stands for," he said. Warned he faces an internal backlash over same-sex marriage: Prime Minister Tony Abbott. Credit:John Veage And in a worrying sign for Mr Abbott, whom the right believes has given his tacit approval for change, Mr Christensen likened the backlash to that experienced in 2009, when former Mr Turnbull tried to support Labor's carbon trading scheme. Mr Turnbull ended up losing the Liberal leadership to Mr Abbott over the issue. "To many it would be both bizarre and a slap in the face to our grassroots members to suggest that the conservative parties adopt a policy which says we don't have a stance on marriage and everyone can be a free agent and vote how they want," Mr Christensen said.

"The party membership didn't like being ignored on the ETS and they won't on this one either." Liberal MP for Deakin Michael Sukkar. Credit:Jesse Marlow Victorian backbencher Michael Sukkar said Coalition MPs owed their voters an obligation to stick by the policy they had taken to the last election. "In my view, every Coalition MP had an unequivocal position on same-sex marriage before the last election," Mr Sukkar said. Tony Abbott with George Christensen. Credit:Andrew Meares

"In my views those MPs should not go against the position they adopted because that would have been a factor in their constituents voting for them last time." Mr Sukkar said the issue should be put to voters in a plebiscite after the next election, perhaps in conjunction with the referendum for Indigenous recognition in the constitution. Tensions boiled over in the last week of Parliament when Liberal backbencher and Canberra Senator Zed Seselja took aim at Assistant Treasurer Josh Frydenberg for breaching his ministerial obligation to advocate party policy. Mr Christensen and Mr Sukkar were the only MPs willing to speak publicly but Fairfax Media understands their views are widely held among the right including in the ministry.

One source said the issue "cost" Bill Glasson, a twice-failed LNP candidate, pre-selection for the Queensland LNP Senate vacancy caused by Brett Mason's retirement. A second source said it was a "factor" in Dr Glasson's overall "poor" campaign but confirmed the former AMA president was "dragged back in" to explain his support for gay marriage in the context of "party policy" and the Liberal National Party's decision to oppose marriage equality. The pre-selection was won by surprise candidate Joanna Lindgren, who opposes gay marriage, abortion and euthanasia.

Dr Glasson was overseas and could not be contacted before deadline. Several Liberals have pointed to a recent interview with Mr Abbott's sister, Christine Forster, an openly gay and prominent campaigner for marriage equality, in which she revealed she had been in contact with supportive federal ministers behind the scenes. One senior Liberal said this showed the Prime Minister was effectively "green-lighting" his favourite ministers to help build momentum for change. "I've been increasingly confident that we would get there before the end of 2015," Ms Forster told Lateline. "Because of communications with Tony, your brother?" host Tony Jones inquired.

"Because of communications with my brother, with other Liberal colleagues who have been working really hard behind the scenes on this, people like Warren Entsch, Senator Simon Birmingham, Josh Frydenberg."

But Ms Forster, a Sydney councillor, dismissed the conspiracy theory, saying she had been simply canvassing the views of her federal colleagues because she was constantly being asked about the issue in public. "I've been speaking to both sides of the argument, I'm not in any way orchestrating anything," she said. Follow Latika Bourke on Facebook Follow us on Twitter