Prime Minister Malcolm Turnbull says same-sex marriage will be legalised by Christmas if the 'Yes' campaign triumphs.
Mr Turnbull has assured the issue will be done and dusted by December before breaking for the holidays and it would "sail through parliament".
"If there is a yes vote we will ensure there is a private members' bill to legalise same-sex marriage and I have no doubt the parliament will deal with that before they will break up in December. It will, it absolutely will," he told .
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"The commitment that I made and the government made... if a majority of those Australian who vote, vote 'Yes' then we will ensure there is a private members' bill.
"Members of government and opposition will be free to vote as they wish and it will be debated."
Mr Turnbull has been a supporter of same-sex marriage, and has previously said he and his wife, Lucy, voted 'Yes' on the issue.
A Newspoll, published in The Australian on Wednesday, shows 59 per cent of eligible Australians have already voted 'Yes', with only 38 per cent voting 'No'.
Traditional marriage supporters would need to win three out of every four remaining votes for the no case to prevail.
The Australian Bureau of Statistics, who is running the survey, says 67 per cent of ballot papers have been returned so far.
The survey closes on November 7 and the results will be released on November 15.
- with AAP
