Liberal MP Liza Harvey says she is resigning her position as Western Australia's Opposition Leader, less than four months out from the state election.
Ms Harvey made the shock announcement on Sunday, sending a written statement to fellow Liberal MPs.
"I am standing aside to give the Liberal Party with a new leadership team the opportunity to reset our election strategy and give the public a real choice at the March election," Ms Harvey said in her statement.
Ms Harvey made reference to the COVID-19 pandemic, saying it had "been extremely difficult for our message to resonate".
"I'm also standing aside to give our very fine candidates the opportunity to be elected as the new generation of members representing the Liberal Party," she said.
"This decision will give them clean air. They are energetic young men and women who will be strong, hard-working members for their communities."
In a brief press conference following the statement being sent out, Ms Harvey described Premier McGowan's administration as a "do nothing" Government.
"They had no achievements," she said.
"While they've done a good job in closing the borders, the difficult job was always going to be coming out of lockdown.
"It's very clear the Labor Government have no plan for this."
Ms Harvey would not take questions from reporters after making her announcement.
She will remain leader until a Liberal partyroom meeting is held on Wednesday to nominate her replacement.
Ms Harvey had faced intense leadership scrutiny amid polling that indicated the party was at risk of a heavy loss at the March 13 election.
She will recontest her seat of Scarborough at the election.
She said she hoped to be a senior member of a future Liberal government.
Health spokesman Zak Kirkup, Shadow Treasurer Dean Nalder and Cottesloe MP David Honey are seen as the most likely successors to Ms Harvey.
Mr Nalder, who was a minister in the previous Liberal Government, has told the ABC he will nominate for the position.
In 2016, the Bateman MP unsuccessfully challenged then-premier Colin Barnett for the leadership, months before the Liberals suffered a heavy election loss.
Mr Kirkup has also confirmed he will nominate for the leadership.
Liberal member for Kalgoorlie, Kyran O'Donnell, said he was contacted by Mr Nalder today and he agreed he would support him becoming leader.
"I think he could do well for our state as the leader," he said.
Mr O'Donnell cautioned against promoting Mr Kirkup, who won his seat of Dawesville by only 343 votes at the last election.
"It would be devastating if the premier just bombarded Dawesville with everything & meanwhile Zak's in other parts of the state trying to help candidates win their election," he said.