Prime Minister Malcolm Turnbull has been forced to defend the government’s plan for a marriage plebiscite amid claims he could face a leadership spill if Coalition MPs defied party policy and backed a free vote in Parliament.

Mr Turnbull sparked speculation on Monday that the government was considering a policy shift when he noted Coalition MPs had the right to break with party policy and cross the floor, including on the issue of same-sex marriage.

But he hosed down that speculation on Tuesday following a news report in the Daily Telegraph that quoted a “senior Liberal” describing Mr Turnbull’s leadership as “terminal” if moderate MPs crossed the floor.

“Our government’s policy position on this issue is very, very clear and it has not changed,” Mr Turnbull said on Tuesday.

“We went to the last election promising that the Australian people would have their direct say on this issue.

“The only reason that plebiscite or vote has not been held, the only reason every Australian has not been given the opportunity to vote on this is because of Bill Shorten’s opposition.”

Speaking in Perth to spruik the government’s PaTH internships program, Mr Turnbull expressed frustration at the media for focusing on the issue.

“I know you are interested in this. Can I tell you – I’ve been in WA now for a couple of days, I have met with hundreds of people from the Mindarie pub to community meetings to schools to the train down to Mandurah – only one person has raised this issue with me,” he said.

“So this is an issue of enormous interest to journalists.”

It comes as MPs prepare to return to Canberra next week – and with speculation the same-sex marriage issue may come to a head during the upcoming parliamentary sitting.

Liberal MPs who spoke against the Coalition’s plebiscite policy and indicated they might cross the floor on the issue have faced threats of pre-selection challenges, according to Sky News.

That included openly gay Goldstein MP Tim Wilson, who said on Monday that he would like to see the issue resolved because it “torments” and “challenges” him on a “daily basis”.

Liberal MP Tim Wilson, who is openly gay, wants to see the marriage debate resolved. Photo: ABC

Mr Wilson said that he had been open about his position on marriage during his pre-selection contest.

Liberal senator Dean Smith, who is gay, is reportedly working on a bill that could be voted on in Parliament if four Coalition MPs cross the House of Representatives to suspend standing orders.

It is widely assumed a bill to legalise gay marriage would pass the House if a free vote were held.

As moderate MPs consider breaking with the party over a free vote, government conservatives are backing a non-binding postal plebiscite as a possible compromise position.

Liberal MP Alex Hawke, the Assistant Immigration Minister, said the plebiscite should be re-introduced to the Senate, with a postal plebiscite to be considered if that failed.

Mr Hawke told Fairfax Media that would put pressure on Labor and the crossbench.

Nationals senator Bridget McKenzie and Liberal Andrew Laming said they were open to the idea, which Immigration Minister and leading conservative Peter Dutton has backed publicly.

Senator Eric Abetz warns colleagues to think carefully

Tasmanian Liberal senator Eric Abetz warned it would be a grave matter if his colleagues crossed the floor to change Australia’s marriage laws.

Senator Abetz said if people voted to “enable Labor/Green policy” Australians would judge them harshly because they would be abandoning the pledge the Coalition took to the last election.

He said that the Liberal Party had a very strong tradition of allowing people to cross the floor, but that he took issue with the idea they might vote to suspend other business to force the Parliament to deal with the issue.

“[It] would in effect set aside the government’s agenda and the government’s control on the floor of the House of Representatives,” Senator Abetz said.

“I think the Australian people would judge us extremely harshly if we had people within the government that voted … to enable Labor/Green policy to be adopted in defiance of that which we took to the Australian people.”

−with ABC