Libby Mettam is tipped to become the West Australian Liberal Party's next leader after David Honey confirmed he will not contest a vote for the top job.
Deputy leader Ms Mettam challenged current leader Mr Honey for the role after the state's Opposition leader, Mia Davies of the Nationals, announced her resignation on Friday.
Ms Mettam said the party had not been as effective as it should have been and an urgent change was required for it to be competitive.
Mr Honey initially said he would fight to keep his job at a special partyroom meeting scheduled for Monday, but a spokesman has since told AAP he would be stepping down.
Mr Honey previously said he would remain the member for Cottesloe if he lost the leadership.
The pair are WA's only Liberal MPs in the lower house after the party was hammered at the 2021 state election.
The Nationals won four seats, and the two parties formed an alliance with Ms Davies as Opposition leader.
The Nationals are expected to announce a new Opposition leader to replace Ms Davies after a partyroom meeting on Monday.