The Coalition's marathon same-sex marriage debate ended in a short-term fix which has reignited internal doubts about the Prime Minister's judgement and leadership.

Two thirds of the joint party room supported traditional marriage and binding MPs and senators to the status quo.

But the Prime Minister said in a late-night press conference this was the last term in which his party could be bound, although the policy it would take to the next election was yet to be settled.

"Our position going into the next election should be that in a subsequent term of Parliament this is a matter that should rightly be put to the Australian people," Mr Abbott said.

It is yet to be decided whether the popular vote will be a plebiscite, where a question can be carried by a simple majority, or a referendum-style vote which would set the far higher bar of needing to be carried by a majority of people in a majority of states.

In the eyes of those in the party who support change, that position resolves nothing.

Even supporters of traditional marriage said the Prime Minister's handling of the day's events was "messy" with one senior Liberal describing it as "madness".

"I have never seen anything as mad as this," the senior Liberal said.

"They were literally making it up as they went along."

Ministers, MPs and senators told the ABC the ramshackle same-sex marriage debate and the slow dispatch of former speaker Bronwyn Bishop have rekindled the same doubts about the Prime Minister's judgement and leadership that led to a party room revolt six months ago.

The debate began in the Liberal Party room at 9:00am yesterday, when the PM blindsided moderates by saying the issue would be decided by a joint party room vote, which includes 21 National Party MPs and senators.

In an impassioned speech, Education Minister Christopher Pyne argued that was tantamount to "branch stacking", given the overwhelming majority of Nationals are opposed to change.

Ministers who don't like party position should resign: Abetz

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Some conservative MPs told the ABC they had decided to bring the matter to a head and that they had enlisted the Prime Minister's support to do it.

They said party moderates should not have been surprised because they had been calling for a vote for months.

While a clear majority of the backbench supported the status quo, half of the ministry argued for a free vote, prompting Senate leader Eric Abetz to say any minister who did not like the party's position should resign.

That sparked a caustic response from Communications Minister Malcolm Turnbull.

"One thing I did learn as leader is that it's probably best to keep the team together," Mr Turnbull said.

"We are eight points behind in Newspoll, 14 points behind in Morgan. Are you seriously saying that having ministers resign would be good for us?"

It is understood Assistant Treasurer Josh Frydenberg quoted the party’s founder Robert Menzies in a passionate speech supporting a free vote, and senator Arthur Sinodinos told colleagues he could not look a gay person in the eye and "tell them they're the son of a lesser god".

One Coalition backbencher said "the final count was 66-33 to keep the status quo".

"This was more like 75 per cent until the executive spoke up," he said.

"It proves the disconnect between some ministers and the grassroots and why we are having such poll problems."

Other frontbenchers expressed their surprise that the vote had been called without warning and without being discussed by either the leadership group or the cabinet.

Deputy Liberal leader and Foreign Minister Julie Bishop said: "I thought we were supposed to be talking about climate change today".

Treasurer Joe Hockey was the first member of the executive to propose a referendum in the next term, which was supported by the Foreign Minister and Prime Minister.

Conscience vote debate will be revisited: Laming

LNP MP Warren Entsch said his same-sex marriage bill would be introduced to Parliament on Monday, but accepted it would not pass if put to a vote.

"I can confirm that the Bill will be introduced on Monday morning when I intend to highlight some of the very personal and heartfelt stories that have led me to take this path," he said.

"I have to concede however that given today's decision, the likelihood of failure, should it come to a vote, is assured."

Mr Entsch also said he was not "angry" about the outcome from the six-hour meeting.

"While I'm disappointed with the outcome, I am not angry and I accept the decision of the party room."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 6 minutes 49 seconds 6 m Christine Forster, sister of Tony Abbott, says all people should be equal before the law

Liberal councillor and Mr Abbott's sister Christine Forster, who is engaged to a woman, said she was very disappointed with the result of the party room meeting.

"I'm feeling very disappointed and ... I fervently wish the vote had gone the other way," she told Lateline.

"For me it goes to core Liberal principles [by] which we are all equal before the law."

Queensland LNP MP Andrew Laming said he argued strongly for a conscience vote.

"There is a very strong and emerging current for this to be revisited but it won't be happening in this election term," he said.

Fellow Queenslander George Christensen was pleased with the result.

"I'm very happy with where we've landed on this," he said.

"It was robust in some respects, but also very healthy and everyone was very respectful."

A Coalition MP said: "[The outcome of the meeting] proves the disconnect between some ministers and the grassroots and why we are having such problems."