Nationals MP George Christensen says federal Liberal colleagues have confirmed to they would cross the floor to vote for same-sex marriage.
Mr Christensen last week crossed the floor in parliament to vote with Labor to protect weekend penalty rates.
He tweeted on Wednesday that he only crossed the floor after a Liberal party same-sex marriage advocate told him other Liberals would cross the floor if the party's policy on a plebiscite was not changed.
The Queensland MP said he had been "hesitant" to vote against the government on penalty rates, as he knew it could be used as a reason for other coalition members to vote for a same-sex marriage private member's bill.
"When told they'd cross anyway, concern was removed," he tweeted.
It is understood a number of Liberal MPs are drafting a private bill to allow same-sex marriage, despite the prime minister insisting the plebiscite remains government policy.
