The Human Rights Law Centre said Paterson's bill was "a Trojan horse to allow unprecedented discrimination".
"[But] I don't believe Australians would welcome, and certainly the Government would not countenance, making legal discrimination that is unlawful today".
If the "yes" vote prevails in the postal survey - to be announced Wednesday - the government has indicated it will facilitate debate on Liberal senator Dean Smith's private member's bill.
"Like millions of other Australians, I will be disappointed if there is a No result, but I will uphold my original commitment and present my Bill to the Senate without any expectation it will be debated", he said.
'For example, the Bill would allow people to refuse to provide goods and services on the grounds of belief, thought and conscience taking us well beyond religious beliefs into unchartered waters.
In the event Australia votes "Yes", the cross-party show of support gives Senator Smith's bill an edge over another proposal from Liberal Senator James Paterson, which would roll back anti-discrimination laws in order to strengthen religious and free speech protections. "I don't think their votes should mean we shouldn't have same-sex marriage, but I do think that their freedoms should be protected and I think my bill is a bill that best does that", he said.
It is not known if Senator Paterson's bill is the same bill that Western Australian Liberal MP Ian Goodenough said a collection of a dozen conservative MPs were working on creating, or if there are still more alternative bills to be put forward. But then after the marriage ceremony, the Bill remains silent on what happens if, say, a school teaches that marriage is between a man and a woman.
S&P declares Venezuela in default
At the meeting with creditors, El Aissami read a statement blaming U.S. sanctions for delays to Venezuela's debt repayments. The lowered rating is the latest strike to the oil-rich but cash-strapped country that's under massive financial pressure.
Treasurer Scott Morrison, the government's most senior "No" supporter, said on Tuesday there would "need to be additional protections than those provided in the Smith bill".
A majority yes vote will see a private members' bill be introduced in parliament to legalise same-sex marriage in Australia, Malcolm Turnbull said in October.
The bill ensures exemptions for ministers of religion and celebrants with genuine belief and allows a limited form of conscientious objection.
"It was part of the journey in Ireland [during the referendum on marriage equality], the issue of freedom to discriminate against people, but that debate lasted a couple of hours because Irish people remember what those signs look like".
"It's already against the law", Senator Brandis said.
"There will be no he or she, no husband or wife, no father, mother - all these words will be gone", the Perth-based Christian pastor said.