With Australia's same-sex marriage poll results due this week, conservatives are asking for protections for parents, school teachers and businesses which continue to defend a "traditional understanding of marriage".

The government has pledged to hold a parliamentary vote to legalise gay marriage before the end of the year should the nationwide survey, held after more than a decade of political wrangling, return a "yes" when results are announced on Wednesday.

But divisions within the conservative governing coalition over how to protect the rights of people who oppose same-sex marriage threatens to derail that timeline.

A draft bill drawn up by Liberal Senator Dean Smith to legalise gay marriage contained exemptions that allow religious organisations to refuse to conduct same-sex marriages. That bill received bipartisan support.

But on Monday another Liberal party senator, James Paterson, unveiled a rival bill that would protect not only religious entities but also parents, school teachers, charities and businesses who oppose gay unions.

"If it is wrong to force a priest to participate in a same-sex wedding against their beliefs, it should be wrong to force a florist or a photographer too," he wrote in The Australian newspaper.

Paterson supports same-sex marriage and describes himself as a religious "agnostic", but insisted the values of gay marriage opponents need to be respected.

He said his bill would also allow parents to have their children "opt out of classes that conflict with their values".

"This upholds the right of parents to control the moral and religious education of their children," he added.

Paterson said would try to reconcile his bill with that put forward by Smith.

But the opposition Labor Party, which backed Smith's bill, denounced Paterson's proposal as a "delaying tactic from the opponents to marriage equality".

"Are we really saying, in Australia today, that you can refuse to serve someone because they're gay? You can refuse to bake them a cake or drive them in your car? Honestly, that is a bridge too far," said Tanya Plibersek, the deputy Labor chief.

Equality advocates also slammed the Paterson bill as aimed at curtailing Australia's discrimination laws.

"Australians are voting to make our country a fairer and more equal place, not to take us back to a time where people can be denied service at a shop," Anna Brown of the Equality Campaign said in a statement.

Turnout for the controversial survey reached almost 80 percent when voting closed last week, with polls indicating a 'yes' vote is imminent.

The conservative government chose an unusual approach for the poll - a voluntary and non-binding postal vote - after an election promise of a national plebiscite was twice rejected by parliament's upper house, the Senate.