Prime Minister Malcolm Turnbull says he has never supported a carbon tax, as debate about a climate policy review process threatens new disunity and political strife within the Coalition.

Backbench MPs have publicly questioned the government's timing and tactics after a formal review of the Direct Action policies was announced by Environment and Energy Minister Josh Frydenberg this week, with backbenchers including Cory Bernardi and Craig Kelly warning against any move towards a carbon tax or similar scheme.

The review will include consideration of whether an emissions intensity scheme for electricity generators, a form of carbon pricing, was appropriate for Australia.

Speaking in Sydney on Tuesday, Mr Turnbull said the planned 2017 process had been expected for years and was part of a suite of policies taken to the past three elections.