Anger is rising within the Abbott government over Malcolm Turnbull's advocacy for gay marriage, with the Communications Minister publicly criticised by two backbench colleagues.

South Australian Senator Cory Bernardi has urged Mr Turnbull to either resign from the frontbench or stop commenting on "fringe issues outside party policy". And West Australian Liberal MP Dennis Jensen said Mr Turnbull's comments on gay marriage were "unhelpful" and not befitting a cabinet minister.

Malcolm Turnbull. Credit:Andrew Meares

Mr Turnbull frustrated some of his more conservative colleagues when he told an interviewer on Sunday that Australia was getting out of step with similar countries on gay marriage.

He said Britain, Canada and parts of the US and South Africa had taken steps to allow gay marriage.