Prime Minister Tony Abbott issues the warning on Wednesday morning. Credit:Alex Ellinghausen Mr Abbott said on Wednesday the issue should be put to the public through a plebiscite following the next election, warning people not to "underestimate the magnitude" of legalising same-sex marriage. Queensland Liberal National Party backbencher Warren Entsch has said he still plans to introduce a private member's bill to legalise same-sex marriage next week. Mr Abbott said on Wednesday that it is "the standard position of our party that if a frontbencher cannot support the party's policy, that person has to leave the frontbench".

"That has always been our position," he told ABC radio. Prime Minister Tony Abbott during his late night press conference on Tuesday. Credit:Andrew Meares "As I said, if it does come before the Parliament, obviously our backbenchers are entitled to vote in the end, wherever way they want. "I would be disappointed if they went against the party position but nevertheless we have always accepted that in the end all votes in our party room for backbenchers at least are conscience votes." Illustration: Ron Tandberg

Mr Abbott acknowledged he had rejected the idea of a popular vote less than three months ago by saying "questions of marriage are the preserve of the Commonwealth Parliament". Mr Abbott said this was his instinct at the time but he had now changed his mind. "Given the nature of this issue and the strength of feeling on the issue in the party room and the community, the disposition of the party room was to go into the next election with a commitment to put this issue to the people in the next term of Parliament," he told reporters. Mr Abbott said a popular vote on the issue was justified because it was such a "personal" and "contentious" issue that has only recently gained widespread support. "Please, let's not underestimate the magnitude of this as a cultural shift," he said.

"Never before in this country or anywhere until very recently has this been regarded as an appropriate cultural norm." Speaking after the Irish referendum supporting same-sex marriage in May, Mr Abbott said: "Referendums are held in this country where there's a proposal to change the constitution. "I don't think anyone is suggesting the constitution needs to be changed in this respect." Opposition Leader Bill Shorten said that a national plebiscite or referendum would waste millions of dollars and accused Mr Abbott of being out of touch. "I think that millions of Australians will have woken up this morning, bitterly disappointed with Mr Abbott," he told Channel Seven.

"I don't understand for the life of me what Mr Abbott has against marriage equality. We shouldn't have to wait for a referendum which by the way will cost tens of millions of dollars. "I think Mr Abbott just needs to move with the times." Follow us on Twitter