Australians appear to be unmoved by anti-same-sex marriage warnings of creeping gender ideology, social destruction, or sexual confusion, with the case for change surging ahead.

With more than a month to go in the government's controversial postal survey, an aggregation of public polling and some recent unpublished research shows the "yes" case for legalising same-sex marriage has maintained its strong lead among ordinary voters.

This is despite the attempts by opponents to introduce other issues such as the Safe Schools program, the rights of children, and a diffuse complaint about increasing political correctness. Respected pollster John Stirton has crunched the numbers based on published polls and concluded that with a majority of votes already cast, the race appears to be all but decided.

"It's very hard to see how the 'no' case could win from here unless an awful lot of people are straight-out lying to pollsters," he said. Formerly a pollster with Fairfax/Nielsen for 17 years, Mr Stirton analysed polls published between August 1, a week before the survey was announced, and October 2.