Queensland Nationals Senator Ron Boswell has injected the issue of class into the gay marriage debate, saying blue-collar workers do not support same-sex marriage.

The senator's comments came as Prime Minister Julia Gillard gave the go-ahead for a debate on gay marriage to be held in the first week of December next year, following a motion proposed by Greens MP Adam Bandt.

Queensland Nationals Senator Ron Boswell.

The 69-year-old senator said a "weak, rudderless, frightened" Labor Party was at the beck and call of Greens extremists he branded the "One Nation of the Left".

He said Labor's attempts to claw back liberal inner-city voters lost to the Greens would ultimately alienate the working class, once "the bread and butter of the old Labor Party".