Tony Abbott
Liberal Warren Entsch will introduce marriage equality legislation to the parliament next month, pending a decision by the selection committee.
It will be co-sponsored by fellow Liberal Teresa Gambaro and seconded by Labor MP Terri Butler.
But the prime minister has reminded coalition MPs it is rare for private legislation to get up in the parliament, amid calls for him to allow them a free vote.
A spokeswoman for Mr Abbott said the joint party room will only consider such bills if they are to be voted on in the parliament - a rare event.
The PM remains opposed to same-sex marriage.
