Senior Turnbull government minister Christopher Pyne isn't aware of any coalition MPs willing to cross the floor to vote on a private bill to allow same-sex marriage.
West Australian Liberal senator Dean Smith is drafting a bill which would allow his party to revisit the issue before the next election.
At present, the party's policy is for a national plebiscite, which if approved would be followed by the parliament passing changes to the Marriage Act.
Senator Smith is hopeful the party room can discuss his bill in coming months and it can be put on the parliamentary program for debate and a conscience vote.
Mr Pyne told Sky News on Tuesday the government's policy on a plebiscite had not changed.
Asked whether coalition MPs could cross the floor, the cabinet minister said: "I'm not aware of anybody even contemplating that."
"There is no proposal at the moment to change that policy."
The coalition holds a one-seat majority in the House of Representatives.