Backbench MP Llew O'Brien will call for a leadership spill on Tuesday.

Mr Joyce, the party's former leader, said he'd informed Mr McCormack earlier that he would have a tilt at the role.

"You can't just sit back and say 'I wish things were better'," Mr Joyce told Sky News on Monday

"I have respect for Mr McCormack, I think he does a good job.

"The National Party has to be on the balls of its toes as we face some of the most challenging times. We have to speak with our own voice."

Mr Joyce has the support of now-backbencher Matt Canavan, despite earlier on Monday saying he was standing by Mr McCormack.

Senator Canavan has resigned from the ministry in order to back Mr Joyce.

"We need a bulldog, we need a fighter," he told reporters in Canberra.

The Queenslander wouldn't say if he thinks Mr Joyce has the numbers to win.

"I have not lobbied other members ... I have no idea about the overall make up of the result tomorrow.

"I think Barnaby has proven himself as a stayer."

Nationals MPs will also vote for a new deputy after Bridget McKenzie resigned on Sunday over the sports rorts scandal.

Water, Drought and Emergency Management Minister David Littleproud is the frontrunner to replace her.

Mr McCormack had earlier dismissed speculation his job was at risk and was confident he would continue.

"There is no vacancy for the leadership, at the moment, of the National Party," he told reporters at Parliament House on Monday.

"I have delivered for rural and regional Australia."

Senator McKenzie would not be drawn on what was likely to happen at the meeting, insisting only that her old role was up for grabs.

"In true National Party fashion, I'm sure there will be a Melbourne Cup field of candidates," she said.

Mr Joyce, who resigned as deputy prime minister in February 2018, talked up his record as Nationals leader.

"We had the maximum number of cabinet ministers we ever had, we won back more seats than we had in about 30 years, we delivered some big changes," he said.

Senator Canavan will not run for the deputy leadership, paving the way for Mr Littleproud to succeed Senator McKenzie.

Backbencher David Gillespie will also throw his hat in the ring for the position of deputy.

The NSW MP criticised Mr McCormack's leadership but refused to say whether he would support a spill motion.

"He needs to do more than the bush-regional media. When you're in a leadership position you've got to do the national stuff as well," Dr Gillespie told reporters.

He said Mr Joyce did his "fair share" of media as the party's most prominent backbench MP.

Veterans' Affairs Minister Darren Chester ruled out contesting the deputy leadership.

He backed Mr McCormack, saying the Nationals leader has the overwhelming support of the party room.

"We don't try and roll people halfway through a term. He is doing a very difficult job very, very well," Mr Chester told Sky News.

Labor leader Anthony Albanese said the concept of Mr Joyce making a comeback was bizarre and showed "how low they have sunk".

Australian Associated Press