Kristina Photios, the wife of NSW Liberal Party powerbroker Michael Photios, has quit the party to speak out against a "vocal minority" of conservatives she says are preventing any progress on climate policy by the Turnbull government.

The Liberal Party must move "back to the centre" and progressive members should stand up and be heard to ensure Prime Minister Malcolm Turnbull is not held hostage to the hard right of the party, Ms Photios told Fairfax Media.

Her unvarnished comments, which will likely have internal ramifications for Mr Photios as the longtime leader of the left or "moderate" faction in NSW, have given an insight into the depth of feeling raging inside the party in a week in which Mr Turnbull was again forced to retreat from a public debate under threat of insurrection from within his own ranks.

"Debate in the Liberal Party is being shut down by a vocal minority of conservatives who are subverting the democratic process," Ms Photios said, singling out former prime minister Tony Abbott and South Australian senator Cory Bernardi as among those "ideologically-driven" Liberals who wield disproportionate influence.