John-Paul Langbroek says he'll step down as Queensland opposition leader.
At a joint press conference, Deputy Opposition Leader Lawrence Springborg also said he was resigning from his post.
Mr Langbroek said he wished Campbell Newman well, after the Brisbane lord mayor announced he'll seek to enter state politics and mount a leadership challenge.
Mr Springborg said it was an enormous privilege to serve under Mr Langbroek, his good friend.
He said he would stand down as deputy.
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"Obviously, people have charted a different course. The ball is in their court," he said.
Mr Langbroek said he would resign on Tuesday.
He said he had the best interests of Queenslanders at heart in making the decision but "the course has been set by others in the party".
Mr Springborg announced his resignation as "a consequence of events in the last couple of days".
He said it was an unprecedented process and Liberal National Party (LNP) MPs would meet at 6pm (AEST) to decide on an interim leader.
"We have never seen this in the history of Queensland politics," Mr Springborg said.
Mr Langbroek said he would recontest his Surfers Paradise seat.
But Mr Springborg would not confirm he'd recontest his seat of Southern Downs, saying he'd discuss it with his family.
However, both men said they would not accept positions in the shadow ministry.
Mr Langbroek said it was for others to decide how well he'd led the party.
"I have no regrets that I'm going to talk about here," he told reporters.
He said it was time to think of the future, not the past.
