Federal Liberal MPs will debate their latest position on same-sex marriage at a special meeting called for Monday afternoon.

Prime Minister Malcolm Turnbull has told MPs to be back in Canberra a day early for the meeting.

The party is deeply divided over whether to change the law to allow same-sex couples to marry.

Mr Turnbull personally favours changing the law to allow same-sex marriage, but he is arguing the party needs to keep its promise to the electorate to hold a public vote, or plebiscite, first.

The meeting is an opportunity for MPs to express their views on the best option for dealing with the long-running issue.

Some Liberals are not ruling out trying to bring on a vote in Parliament within weeks, but others insist strongly the Coalition must stick to its pledge to have a plebiscite.

It is possible the Liberal meeting and a subsequent one which also includes Nationals MPs will decide to try again to have a plebiscite.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 8 minutes 7 seconds 8 m Emma Alberici speaks to Warren Entsch about the upcoming meeting.

If the Senate again refused to pass the plebiscite, the fall-back position may be a postal ballot on the issue.

The same-sex marriage issue has exposed deep divisions within the Coalition and that tension is set to overshadow the early weeks of Parliament with some characterising it as a test of Mr Turnbull's leadership.

Liberal MP Warren Entsch — who has led the push to allow same-sex marriage — welcomed Monday's meeting.

"I am looking forward to it, I think it is great, we have been hoping for that for a while," Mr Entsch said this afternoon.