Same-sex bill won't come to vote: Abbott

Prime Minister Tony Abbott doubts whether a new bill legalising same-sex marriage will ever come to a vote in the Senate.

Liberal Democrat David Leyonhjelm last week introduced a private bill to allow same-sex marriage, leading to renewed calls for Mr Abbott to allow coalition MPs and senators a conscience vote.

But the prime minister says such bills don't usually go to a vote.

"If this one is different, well, obviously the party room will consider it," he told reporters in Canberra.

Senator Leyonhjelm last week said the prime minister had counselled him against the bill because it would cause trouble for the government at a time when it was already facing a number of challenges.

Labor MPs already have a conscience vote on same-sex marriage.