'I was not pushed': George Christensen resigns as Nationals chief whip

George Christensen will resign as the Nationals chief whip after leader Barnaby Joyce gave him an ultimatum over his increasing outspokenness.

The resignation was jointly agreed to after Mr Joyce told the north Queensland MP for Dawson he had to make a choice between saying things independently of the party or keeping the whip job.

It will take effect from Thursday when Nationals MPs and senators meet to elect a replacement, with Damian Drum expected to be the front runner for the position.

"I made the decision to resign because my continued outspokenness on a variety of issues was obviously incompatible with the position of Party Whip in the long term," Mr Christensen said in a statement.

"It was my decision to resign; and my decision alone. I was not pushed by anyone.

"However I did feel some of my colleagues may have been aggrieved that the enforcer of discipline was being somewhat ill-disciplined himself.

Mr Christensen reportedly assured Nationals leader Barnaby Joyce that he was not resigning to join Pauline Hanson's One Nation.

"Over the past week as I’ve reached this decision, Nationals leader Barnaby Joyce has been incredibly supportive, and said he would have supported whatever decision I made on the matter," he said.

"I thank him and the rest of the Nationals team for the great honour of serving as their chief whip over the last six months."

The decisions comes just days after Mr Christensen vowed he would not resign, adding to Prime Minister Turnbull's growing headache over rumors of instability in the government.