The Prime Minister had said he wanted the vote to be held this year.

However a spokesperson for Mr Turnbull told Fairfax Media that Special Minister of State, Scott Ryan,  received advice last week from the Australian Electoral Commission (AEC) advising the government to push the vote back.

"The government has always said that a decision on same-sex marriage will be made by a vote of all Australians in a national plebiscite to be held as soon as practicable," the spokesperson said.

"That commitment has not changed. Late last week, the AEC provided advice to the Special Minister of State that strongly recommended against the conduct of a plebiscite this calendar year."

News Corp reported on Saturday night that a timeline for the vote would now be announced in September and that the question expected to be asked is: "Do you approve of a law to permit people of the same sex to marry?"

The report said the government rejected other options for questions – including those relating to gender – following focus groups.

However the government denied that a date or a question had been finalised.

"The mechanics of the plebiscite, including the specific question and also the timing, are subject to the usual cabinet processes," Mr Turnbull's spokesperson told Fairfax Media.

"No decisions have as yet been made."

The $160 million plebiscite remains controversial inside and outside the Coalition, with reports in June suggesting some government MPs would ignore the will of the people if same-sex marriage was approved via the compulsory vote.

Opponents of the vote say it will fuel bigotry and homophobia.

Despite a split among gay marriage supporters about the need for the vote – opponents argue the matter should be decided by Parliament – a structured "yes" campaign is already forming ahead of the formal announcement of the vote date.

The ALP still hopes Parliament will decide the matter, with Opposition Leader Bill Shorten intent on pushing through a private members' bill to legalise gay marriage with a vote of MPs.

Mr Shorten has called the vote "Malcolm Turnbull's Brexit", seizing on similarities between Mr Turnbull and the former British prime minister David Cameron, who reluctantly called for the Brexit vote to appease his party, only to have the move backfire.

Mr Turnbull has been quoted as saying he expected the same-sex vote to "sail through".

For the plebiscite to go ahead, both the Senate and the House of Representatives must approve it. MPs must then return to Parliament to rubber stamp the outcome, the point at which it is feared Coalition opponents may block a "yes" vote.

CORRECTION: An earlier version of this article said the plebiscite would be held on February 27. This has not been reported or announced by the government.