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than a month to go in the government's controversial postal survey, an aggregation of public polling and some recent unpublished research shows the "yes" case for legalising same-sex marriage has maintained its strong lead among ordinary voters.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