A federal Liberal candidate has apologised for linking same-sex marriage with paedophilia during the marriage equality debate, after being questioned by The Age.

Gurpal Singh, a lawyer and lecturer who is running to take the safe Labor seat of Scullin, said during a radio interview in 2017 that legalising same-sex marriage could open the gates to more sexual abuse of children.

Gurpal Singh, Liberal candidate for Scullin in Melbourne's northern suburbs. Credit:Liberal Party

He also slammed the Coalition government as weak for holding a postal vote on the issue, insisting it should have settled the matter in Parliament.

Mr Singh made the comments while campaigning for the no vote during the same-sex marriage plebiscite.