THE Liberal Party has split over same-sex marriage, with the Right launching a determined push to head off a conscience vote.

Conservative senators Cory Bernardi and Zed Seselja hit out at Assistant Treasurer Josh Frydenberg, who has declared his support for both a conscience vote and a “yes’’ vote allowing same-sex marriage.

Senator Bernardi called for Mr Frydenberg and frontbench colleagues also in favour of a yes vote — Kelly O’Dwyer, Malcolm Turnbull and Simon Birmingham — to resign for speaking against party policy.

The Right’s push back against the “inevitability” of both a conscience vote, and a yes vote in Parliament, took several days to gain momentum. The absence of ministers Eric Abetz, whose wife is ill, and Kevin Andrews, who is in Asia, had initially slowed the Right’s response.

One Liberal MP told the Herald Sun that with overwhelming support from Labor, only about 25 Coalition yes votes would be enough to get the vote through. Another said those who led the push for same-sex marriage were abandoning the Liberal base.

Two other Victorian frontbenchers, Environment Minister Greg Hunt and Nationals MP Darren Chester, have not formally declared their position but made clear they are likely to support a yes vote.

The issue was not raised in the Coalition party room on Tuesday, which was expected, as the senators are not in Canberra this week. It also seems likely the Liberal party room will not vote on whether to have a conscience vote until Parliament resumes in mid-August.

Senator Seselja said on Tuesday that he didn’t believe the Liberals’ current position — to oppose any change to the Marriage Act — should be altered, and he said ministers should publicly support that position.

Senator Bernardi, who was forced to resign from Mr Abbott’s front bench three years ago after linking the push for same-sex marriage with bestiality, attacked his colleagues who had spoken publicly about their support for the change.

“Malcolm Turnbull has been agitating (for marriage equality). He’s in Cabinet. You’ve had the Prime Minister’s sister say the other day Josh Frydenberg has been involved ... Simon Birmingham has been involved ... Kelly O’Dwyer has been involved,” Senator Bernardi told the BuzzFeed website. “These people have frontbench responsibilities. It is their obligation to reflect the party’s view and not indulge in their own frolics and fantasies. If they don’t like it ... go to the back bench and they can say and do whatever they please.”

ellen.whinnett@news.com.au