Mr Barnett said he would accept the position of leader if his parliamentary colleagues voted for him in a party room meeting tomorrow.

But he also indicated he expected to stand for the seat of Cottesloe, throwing into doubt the plans of the Liberals' star recruit.

It follows the resignation of former leader Troy Buswell yesterday, after a turbulent six months in the job.

Mr Barnett had earlier announced he would leave politics at the next state election.

Former Chamber of Commerce and Industry executive director Diedre Willmott was preselected for his seat of Cottesloe.

But he said today that he would "relish" taking on the Government at the next State election.

"This State and its people deserve better," he said.

He was "totally" committed to winning the election, but would not say if he would stay in parliament if the Liberals lost.

Mr Barnett's decision to stand in Cottesloe leaves the future of Ms Wilmott, a former chief-of-staff to Liberal Premier Richard Court, in the balance.

She said earlier she was "standing firm" in her intention to run for the Liberals, and expected to do so in Cottesloe.

"My strong message to the party is that there are a number of options," she said.

"They need to find one that involves me. They came and asked me to run because of my background and I still intend to run."

Mr Barnett, who previously led the party between 2001 and 2005, said the matter of what to do with Ms Willmott was "a complicated issue", but it was for her and the party to resolve.

"It's not something I should be involved in," he said.

"I've known Diedre Willmott for a long time. I hold her in the highest regard. Obviously Diedre would make a very fine member of parliament."

Capel MP Steve Thomas earlier said other Liberals with leadership aspirations, such as himself, should put them aside for the sake of the party.

"The time is here for us to do our jobs and have Colin Barnett in the leadership," Mr Thomas said.

"It should be done even without nominations. It is too late at this stage to try and elect somebody new."

Mr Thomas said while Mr Barnett had already announced his retirement, he was tried and tested and popular with the electorate.