Laws to allow same-sex marriage will be debated in the Senate this week, but Labor insists it's a stunt that won't produce any real result.
The Greens on Tuesday shot down debate on its own marriage equality bill, as Liberal Democrat David Leyonhjelm tried to bring the legislation on for a vote this week.
The unsuccessful move was one of several crossbench attempts to embarrass the government and the Greens by forcing them to avoid debating their own legislation, as they forge ahead with plans to get changes to the way Australians vote for the Senate passed this week.
The Greens instead challenged Labor to bring the same-sex marriage bill on for debate on Thursday, during the time allocated for private bills.
Opposition Senate leader Penny Wong has agreed to have the Greens bill debated instead of her own but insists it's a stunt.
It's a one-hour debate with no guarantee of a vote, instead of the definite vote that would have been delivered by Senator Leyonhjelm's amendment.
"This is manifestly inadequate, and the Greens know it," she said.
"They take this position knowing one hour is not sufficient time to debate marriage equality and the government can and will frustrate a vote."
She said the Greens valued their "dirty deal" with the government on Senate voting changes over their own principles, voting with the likes of gay marriage opponents Cory Bernardi and Eric Abetz.
Greens leader Richard Di Natale insisted the matter could be brought to a vote on Thursday.
He said Labor had sat with Senators Bernardi and Abetz on issues like keeping children in detention and dropping bombs on Syria.
"There has been no party that has stood in resolute opposition to this government's agenda more than the Australian Greens," Senator Di Natale said.
Senator Leyonhjelm said he would have had the numbers to get the legislation passed in the Senate this week.
"If they are willing to walk away from marriage equality, what won't they jettison?" he said.