Liberal MP Tim Wilson, a campaigner for same-sex marriage, said the Paterson bill is unworkable and would not pass parliament.
"My own view is that people, like ministers of religion, should not be obliged to conduct a ceremony of marriage against the teachings or doctrines of their church and Senator Dean Smith's bill does provide an exemption of that kind", he said. Support for SSM was highest in the ACT, with a 74%/26% yes/no split, while NSW was the lowest, at 57.8%/42.2%, while 133 of 150 electorates in the lower house returned a majority yes vote.
The Senate will be asked on Wednesday to support a move to introduce draft laws allowing same-sex marriage on Thursday.
In a media blitz on Wednesday night Malcolm Turnbull stressed that democracy had spoken and the government would "get the job done" and make good on their promise to follow through with the Yes vote on same-sex marriage.
Mr Brandis expects the Senate will deal with the bill by the end of the next sitting week on November 30.
Greens Leader Richard Di Natale is among those warning the legislation must not be used as a Trojan Horse to entrench discrimination.
"I don't see the case is made for massive amendments", he said of the Smith bill.
Already we've seen conservatives and moderates within the Coalition position themselves behind one of two bills proposed to make same-sex marriage lawful.
It will be supported by Labor and the Greens even though the minor party plans to present amendments.
"I will now work constructively with my parliamentary colleagues over the coming weeks on amendments to ensure that the strongest possible protections for the freedoms of all Australians are enshrined in the final legislation", he said.
"I don't believe Australians would welcome, and certainly the Government. would not countenance making legal, discrimination that is illegal, that is unlawful today", he said.
While members will be free to suggest any amendments on new legislation Mr Turnbull said calls for such action would have "virtually no prospect of getting through the Parliament".
"I think fundamentally we know what the law change is required to look like..."
In contrast, Education Minister Simon Birmingham, who is also in favour of same-sex marriage, said the Smith Bill had been scrutinised by a committee and based on an exposure draft produced by the Attorney-General.
"It's clearly a good bill to start with", he said.
Should the vote go that way, Smith is prepared to introduce his marriage equality bill immediately. Liberal senator James Paterson's bill is also far more stringent. "They have voted for love, they have voted for fairness, they have voted for commitment, they have voted for respect", he said.