Give us details, Labor says on plebiscite

Federal Labor wants to know when the government plans on holding its planned plebiscite on same-sex marriage, saying it's unlikely to be this year.

Labor wants the Turnbull government to reveal details of its proposed national vote on gay marriage. (AAP)

Federal Labor wants the Turnbull government to reveal details of its proposed national vote on gay marriage, warning it's looking increasingly unlikely to be held before year's end.

Attorney-General George Brandis is consulting the electoral commissioner about the planned plebiscite before he takes a submission to cabinet, but he concedes if it isn't held in coming months it will be conducted in the first part of 2017.

"Not withstanding repeated statements by Mr Turnbull and Senator Brandis earlier in the year that this plebiscite would be held before the end of the year it's now looking extremely unlikely," Labor's spokesman Mark Dreyfus told reporters in Sydney.