Plebiscite bill passes lower house

The federal government's doomed plan for a plebiscite on same-sex marriage has passed parliament's lower house.

Debate on the enabling bill was cut short on Thursday, denying about 20 Labor MPs a chance to speak, and sent to a vote 10 days after it was introduced.

With Labor and the Greens both voicing their opposition to the proposal, however, it is unlikely to clear the Senate.

Prime Minister Malcolm Turnbull has repeatedly refused to say whether he has a "Plan B" if the plebiscite - an election promise - is killed off.

Independent Andrew Wilkie earlier challenged coalition MPs to cross the floor and support either a Labor or crossbench private bill for marriage equality once the national vote was "dead and buried".

"If you're in this place in the pursuit of the public interest, then that's what you'll do," he said.

Mr Wilkie thinks there's enough people of "good heart" in the government who will see the sense in dealing with the matter in parliament.

He rejected the argument that would bring about the destruction of Mr Turnbull.

"In fact, it could be the saviour of the prime minister," he said.

Government frontbencher Darren Chester said he does not see a credible pathway to marriage equality in this term of parliament other than through a plebiscite.

The Nationals MP has only recently changed his view to support same-sex marriage.