MALCOLM Turnbull's deputies are urging colleagues to get behind the Prime Minister as speculation mounts that he could face a leadership challenge from Peter Dutton at a 9am party room meeting.

Defence Industry Minister Christopher Pyne sent a blunt warning to colleagues pushing for a leadership spill that Australians are "thoroughly sick of instability and backstabbing", while Energy Minister Josh Frydenberg says there will be a high cost if the party chooses to topple Turnbull.

Dutton's supporters are doing the numbers ahead of a crucial Liberal Party room meeting at 9am. And if they don't strike today, it's expected Mr Turnbull's leadership won't survive past mid-September when the next Newspoll drops.