Buswell, Johnson in shadow ministry

State liberal member Rob Johnson has regained his police portfolio in opposition leader Colin Barnett's shadow frontbench reshuffle, as Troy Buswell takes on treasury and commerce.

The newly re-elected Mr Barnett asserted his brand of authority when he unveiled his frontbench today, giving Mr Johnson back the police and corrective services after he was stripped of the portfolio nearly two months ago.

Then leader Mr Buswell dumped Mr Johnson in June after he threatened to resign over the scandal between former Liberal MP John McGrath and Brian Burke.

Mr Buswell was today appointed treasury spokesperson and will also handle the commerce, small business and housing portfolios.

Mr Barnett appealed to voters to give Mr Buswell another go after his chair-sniffing and bra-snapping antics made headlines internationally.

"I simply say to the people of Western Australia, here is a young man who is in his first term as a parliamentarian," he said.

"He has immense talent. He's made some mistakes. He's apologised.

"In the spirit of the Olympics give him another go. Let him prove himself and he will prove himself through this election campaign.

"He can take a major role and prove himself to the people of WA."

New recruit Liz Constable has been allocated public sector management and government accountability.

The 64-year-old former Liberal MP had left the party more than 15 years ago in protest at the dealings of Liberal powerbroker Noel Crichton-Browne.

Ms Constable has held her western suburbs electorate since 1991 as an independent.

Deputy leader Kim Hames has been given health and Indigenous affairs while Steve Thomas takes on environment and climate change.

Norman Moore will look after resources development and mines, and Peter Collier holds the education and training portfolio.

Mr Barnett also announced that former Chamber of Commerce and Industry policy director Deidre Willmott will not contest the state election, which will be held on September 6.

Ms Willmott was previously the endorsed Liberal candidate to contest the seat of Cottesloe. She stepped aside earlier this week when Mr Barnett was elected opposition leader on Wednesday.