Updated

Australian lawmakers who fear a national survey will reveal that most voters want marriage equality are moving to wind back anti-discrimination laws to reduce barriers for people who would boycott gay weddings.

Almost 80 percent of Australia's registered voters have responded to a postal survey on whether Parliament should lift the country's prohibition on same-sex marriage. Opinions polls show most Australians support gay marriage.

The survey results will be announced on Wednesday, but debate is intensifying on whether Australians who would refuse to provide gay weddings with a celebrant, venue, flowers or a cake should have added protection against anti-discrimination laws.

Prime Minister Malcolm Turnbull, a gay marriage advocate, on Tuesday ruled out downgrading anti-discrimination laws.