Former High Court justice Michael Kirby says a plebiscite on same-sex marriage will create a dangerous political precedent in Australia where MPs avoid making decisions on controversial issues, instead opting for unnecessary and expensive popular votes.

The government is expected to try to pass enabling legislation for a nationwide plebiscite in coming weeks, before a possible vote in February asking Australians if they agree people of the same sex should be allowed to marry.

But Justice Kirby, who served at the High Court from 1996 until 2009, said plebiscite votes were "alien" to Australia's system of representative democracy and the campaign would drive hatred and abuse towards gay and lesbian Australians.

He said Australian voters had rarely supported referendum questions and there was no reason a plebiscite would be any different.