Conservative senators are pushing for a handful of key amendments to same-sex marriage laws, aimed at boosting protections for parents, civil celebrants and faith-based charities.
The Senate will begin dissecting the finer details of a bill to legalise same-sex marriage on Tuesday after debating the overall legislation late into last night.
Liberal Senator James Paterson has abandoned attempts to allow bakers, florists and other businesses to reject the business of same-sex couples.
But Senator Paterson and Liberal colleague David Fawcett have authored amendments which would include two definitions for marriage.
Marriages between men and women would be recognised separately to marriages between two people.
Senator Paterson said his proposal "achieves the best of both worlds" and there would be no legal difference in how married couples were treated.
"It does allow same sex couples to marry but it doesn't unnecessarily abolish the old definition of marriage, which many Australians still sincerely believe in," he told ABC radio on Monday evening.
Parents would also be able to pull their children from classes if they don't agree with their teachings on marriage.
Senator Paterson rejected suggestions from Education Minister Simon Birmingham that such attempts could be unconstitutional, saying: "The advice that I have is that it's not."
People who hold traditional views of marriage would be shielded from "adverse action" taken against them by governments or agencies, and civil celebrants would be able to refuse to marry same-sex couples.
Attorney-General George Brandis and crossbencher David Lleyenholm have suggested similar exemptions, which would already apply to religious ministers and celebrants under the cross-party bill.
Labor senator Helen Polley, who opposes same-sex marriage, last night spoke of the need for to protect parental rights and religious freedoms.
"If someone wishes to publicly or privately object to a change in secular marriage, they should not be persecuted," Senator Polley said.
But her Tasmanian Labor colleague Carol Brown came out swinging against the proposed changes.
"The religious freedom arguments and proposed amendments are nothing more than last ditch attempts to delay what people now need to accept is inevitable and the will of the Australian people," Senator Brown said.
NSW Labor Senator Doug Cameron was even more blunt in his assessment.
"I don't want religion stuffed down my throat by anyone. It's unacceptable to me and it should be unacceptable to this parliament," he said.
Greens senator Nick McKim told the Senate if amendments were added to the marriage equality bill which increased discrimination, he would vote it down.
