Senator Joyce said it seemed from anonymous sources that "the cause of the discontent in the Liberal Party about the Coalition revolves around me".

It would be a "bad outcome" if the federal Coalition split or the merged Liberal National Party in Queensland fell apart, he said. The only way to lance the boil was for his critics, if they could, to get someone to say he should leave the Coalition.

Senator Joyce's challenge is exposing deep tensions within the Coalition, which some Liberals fear could soon be at risk, adding further to Opposition Leader Malcolm Turnbull's serious troubles.

Senator Joyce said he would step aside if the "proper people" in the Liberal Party said he should. He did not name Mr Turnbull but he was obviously referring to him as the "appropriate person".

The high profile of Senator Joyce and other militant Nationals, especially over emissions trading, has unsettled and angered many rural and regional Liberals, who feel under political pressure.

One long-time critic of the Nationals, backbencher Alby Schultz, from NSW, said Senator Joyce should not just talk about leaving the Coalition, but do so.

Mr Schultz said Senator Joyce would not be missed. He would be followed by a "small gaggle of geese" in the Senate, but he did not have much support among House of Representative Nationals.

Mr Schultz said many Liberals believed the Nationals should walk out of the Coalition on a permanent basis.