Labor wants marriage vote before election

A free vote on marriage equality should be held before an election campaign, Labor says.

Deputy Opposition Leader Tanya Plibersek says same-sex marriage will become an election issue unless Prime Minister Malcolm Turnbull puts an end to the plebiscite "farce".

"Given the expense of recalling parliament, Malcolm Turnbull could use the opportunity to hold a free vote on marriage equality before he runs off to an election campaign," she said on Saturday.

"The last thing this country needs is an election dominated by divisive rhetoric against LGBTI Australians and their families."

Labor has vowed to introduce marriage equality legislation into parliament within 100 days if the party is elected.