NSW Premier Mike Baird has backed his "mate", Prime Minister Tony Abbott, ahead of a potential leadership spill when the federal Liberal party room meets on Tuesday.

Mr Baird said people had criticised and underestimated Mr Abbott his entire career, including his ability to lead the Liberals, be an effective Opposition Leader and then become Prime Minister.

"Mates": NSW Premier Mike Baird and Prime Minister Tony Abbott. Credit:Daniel Munoz

"All along the way he has proven his doubters wrong," Mr Baird said. "My hope is that that's exactly what he does. That, despite the current circumstances, he proves the doubters wrong."

Mr Baird was speaking on Friday amid speculation about Mr Abbott's leadership, shortly before Western Australian Liberal MP Luke Simpkins announced he would put forward a motion to spill the position at Tuesday's party room meeting in Canberra.