Senior government ministers have labelled the Smith bill a good "starting point" for parliament's consideration.
Law Council of Australia president Fiona McLeod said his proposal "goes well beyond the issue of marriage in a number of crucial respects".
That will be all for nothing - or the $122 million cost of the survey - if a "no" vote prevails. "Australians upheld their end of the bargain by voting en masse, now it's time for Parliament to uphold its end of the same deal".
"The government does not, would not countenance making legal discrimination that is illegal", Turnbull told reporters.
"If the result is Yes, our politicians will need to follow through on a Yes result by passing a fair bill that supports true equality". "Honestly, that is a bridge too far", said Tanya Plibersek, the party's deputy leader.
"I note that I was the one saying it was going to be the highest vote", he said.
If they do, the government, led by George Brandis in the Senate, a supporter of SSM is likely to enlist cross-party support to guillotine debate and push through the legislation. All amendments would be subject to a free vote of Coalition, Labor and crossbench MPs. The legislation allows clergy and religious organisations to refuse to marry gay couples.
Mr Goodenough said the alternative Bill could also be introduced into the Senate this week. We know that's the real slippery slope, when you unravel anti-discrimination protections, and I don't think Australian people want that.
Fellow Liberal Dean Smith also has a private bill ready for parliament. 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.
Labor Senator Penny Wong said she hoped the Prime Minister would stand up against the suggested laws.
"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".
Under Senator Paterson's plan, it would also allow any person or business to refuse to co-operate with the staging of same-sex weddings, protecting them from civil litigation under discrimination laws.