The yes vote is prevailing in the same-sex marriage postal survey, much to the delight of Malcolm Turnbull.
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 prime minister is pleased Australians are embracing the survey.
"Certainly Lucy and I voted yes and I would be delighted if there was a yes vote recorded," he told the Nine Network.
The Australian Bureau of Statistics says 67 per cent of ballot papers have been returned.
"We may well see a participation rate over 70 per cent - that would be extraordinary," Mr Turnbull said.
"That will prove that we were right. Australians did want to have their say and they're having their say."