George Christensen has used the resignation of Barnaby Joyce to call on the National party to formally end its coalition with Malcolm Turnbull’s Liberals.

The outspoken Queensland MP posted on Facebook that in the absence of an elected federal leader, the National party should push “the reset button” and slash the ties of their 95-year partnership with the Liberals.

He labelled the Turnbull government an “aimless party” of “leftward drift” that was “shackling” the Nationals.

Christensen, who was rebuked last week by Turnbull for posing with a gun aimed at “leftie punks”, has a long history of speaking out against Liberal and National moderates.

In December, he told the conservative columnist Andrew Bolt he would quit the Coalition if Turnbull remained leader, but then backed down, and in February last year, he resigned as chief Nationals whip after he repeatedly contradicted party policy.

On Monday, the Nationals party room will meet to elect a new leader. The New South Wales MPs David Gillespie and Michael McCormack have announced they will run, and the latter is tipped to win.

On Saturday, Christensen said that whoever won should sever the party from the Liberals.

“The National party must ... put our people first,” he said. “If that means ending the coalition with the Liberal party and instead supporting their Liberal government, with conditions attached, then we owe it to those we represent to consider our options.

“Our formal coalition with the Liberal party has proved successful over the years but it has always been a compromise and, right now, that compromise is becoming increasingly difficult to accommodate.

“I believe the formal Coalition is too restrictive ... I need the support of the National party, not the shackles of an aimless Liberal party.”

The Liberal Nationals MP, who is facing a large One Nation vote in his seat of Dawson, pinpointed immigration and the sale of agricultural land as issues behind the split.

Earlier on Saturday, Turnbull denied that the Joyce saga had weakened ties between the Liberals and Nationals.

“There are no issues between the Nationals and the Liberal party in relation to this at all,” he said. “The Coalition is strong and enduring ... we have a 95-year-old political alliance.”