"I'm hoping that we have a conscience vote," he said. Assistant Treasurer Josh Frydenberg has signalled changes to superannuation could come in a second term. Credit:Chris Pearce "I don't think we should have a situation where ministers go against party policy."

"Whether ministers and parliamentary secretaries like it or not the Liberal National Coalition's policy is to support the retention of the definition of marriage as outlined in the Marriage Act," he said. Nationals MP George Christensen (right) says a petition calling on Prime Minister Tony Abbott to block him from attending a Reclaim Australia rally is "intimidation". Credit:Alex Ellinghausen "That is the policy of the party room. That is the policy endorsed by our organisational wings. "Party commentary to the contrary is disloyal to the party room and to our grassroots members." Mr Frydenberg is one of several ministers who have campaigned for gay marriage while serving in the executive. Others include Environment Minister Greg Hunt and the junior minister Simon Birmingham.

Cabinet minister Malcolm Turnbull first declared his support in March 2012 when he was a shadow minister, also telling Q&A: "I would not be troubled if gay couples were able to have their relationships, their unions termed marriage." As a minister, in 2013, Mr Turnbull advocated a free vote for the Coalition, which would release frontbenchers from their obligation to vote along cabinet lines. Liberal senator, and factional foe, Cory Bernardi berated Mr Turnbull at the time and called on him to abide by cabinet solidarity or quit the executive if he preferred to freelance on social issues. Despite speculation that Liberal MPs would use a regular party room meeting on Tuesday to raise the issue of a free vote, the issue was not discussed. Any MP or senator could raise the matter from the floor, but none took the opportunity.

On Monday, Prime Minister Tony Abbott pointedly stressed that "every single" Coalition member would be focused on the budget for the next few weeks. Many senators were also away from this week's meeting due to Senate estimates. Marriage equality advocates believe there may be enough support in the Parliament to pass a bill to legalise gay marriage now that marginal Liberal MP Sarah Henderson has also declared her support. There are three bills currently sitting in the Parliament to legalise gay marriage, put forward by the Greens, Liberal Democrat David Leyonhjelm and Labor leader Bill Shorten. However none are likely to succeed as Mr Abbott has called for a cross-party bill which the entire Parliament will own as opposed to one political party. Ms Henderson backed a cross-party bill and told the ABC on Tuesday that the party's base was shifting in favour of gay marriage, which opinion polls show the majority of the public also supports.

"I do think there is a shift, even amongst the Liberal party base. Even a few years ago, people [were] saying to me 'I wouldn't support same sex marriage at all' and now I do think there is a shift," Ms Henderson said "For younger people in my electorate there is rarely a person I meet who does not support same-sex marriage and we have to govern for the present of course but we also have to govern for the future. "And I think it's the way that Australia needs to go." As a backbencher, Ms Henderson is free to declare her position without recrimination. But government ministers are expected to abide by party policy unless a free vote is declared after a debate in the party room.