Prime Minister Malcolm Turnbull has declared a Yes vote in the same-sex marriage survey will have people see "Parliament at its best" as he seeks to play down divisions among his MPs over new religious protections.
Labor frontbencher Penny Wong said everything Senator Canavan said needed to be judged against his intention to "loudly and aggressively" campaign against marriage equality.
Australians have voted in support of same-sex marriage, paving the way for parliament to legalize gay unions before the end of the year. Borrowing from American conservative tactics, it would legalize marriage for same-sex couples, but also create broad "religious freedom" exemptions for business owners who want to refuse service to those couples.
Others in the government, including the chief law officer George Brandis, think that would be unconscionable.
"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.
Parliamentary opponents of same-sex marriage such as Matt Canavan and Cory Bernardi are standing firm. A gazumping "yes" win would weaken the conservatives' ability to agitate, while a narrow victory would give them ammunition to defend the interests of those who voted "no".
On Tuesday, a group of cross-party senators backed a same-sex marriage bill penned by Liberal Senator Dean Smith.
It is that bill which has been chosen by government ministers as their preferred starting point.
"A yes vote can not and should not and must not become a moment where others try to unravel existing anti-discrimination law", he said.
It is anticipated that Senator Smith's bill will be introduced into the Senate on Wednesday afternoon, with debate to begin on Thursday, though it is expected to be subject to numerous amendments.
As a conscience vote, there's no need for a consolidated party room position on any element of the bill.
If Turnbull has fumbled a basic human rights issue that other comparable countries like New Zealand have already resolved just to appease a conservative but vocal minority faction fronted by ex-PM Tony Abbott, then he will have miscalculated the generosity Australians feel towards his increasingly tenuous government.