Instead, Mr Broad said he expected the federal Coalition’s position on same-sex marriage would not change.

The Sunday Telegraph has reported that up to 12 Liberal Party members in the House of Representatives and Senate will approach Prime Minister Malcolm Turnbull with a call to drop the plebiscite.

Under former prime minister Tony Abbott, the Liberal and National parties agreed to have Australians participate in a non-binding referendum-style vote on whether or not to legalise same-sex marriage.

After winning a leadership spill, Mr Turnbull pledged to continue the policy, which was taken to the July double dissolution election.

During a previous round of speculation that the government would drop the plebiscite and move to a free vote in parliament, Mr Broad threatened to withdraw support for the government. 

“The government that I am a part of and will remain a part of is conditional on the fact that the only way that there will be a change to the Marriage Act in this parliament is a plebiscite,” Mr Broad said in October.

“My position as a member of the government is very clear on that.”

Under the terms of Mr Broad’s prior threat, we would “probably” continue to support the government in votes of confidence and budget supply, potentially averting the need for an early election or intervention from the Governor General.

Asked on Sunday of he would still carry out the threat if the plebiscite was abandoned, Mr Broad said the Coalition should keep its election promise.

“Australians expect government to honour party room-determined policies that are taken to elections,” he said.

“The policy of the government is to allow every Australian to have a vote to determine the definition of marriage.”

Mr Broad’s prior threat to withdraw support to the government, which currently holds power with a one-seat majority, earned him a rebuke from Nationals leader and Deputy Prime Minister Barnaby Joyce.

“Quite obviously, any person in parliament making a statement that they’re going to bring down the government, I don’t think the Australian people want that,” Mr Joyce told the ABC.

Mr Broad has pledged to vote for or against same-sex marriage on the basis of how people vote in the Mallee electorate rather than the overall national plebiscite result.