NEWLY elected WA Premier Mark McGowan has revealed his new cabinet with Labor stalwart Alannah MacTiernan included in the mix, while Margaret Quirk was the surprise casualty.

WA Labor had a shadow cabinet of 20, but said it would have to reduce that number from 21 to 17, meaning the party always planned to parachute former federal MP Alannah MacTiernan into the ministry, as revealed on Sunday.

Ms MacTiernan has returned to state politics with an upper house seat and was well regarded as WA's planning and infrastructure minister from 2001 to 2008.

Ms Quirk, who held onto her seat with a convincing swing of about 14 per cent, handled portfolios including emergency services, bushfire preparedness, and seniors and ageing in opposition.

She also chaired several parliamentary inquiries, including a 2014 investigation into former WA treasurer Troy Buswell's car crashes, which concluded police handling of the incident was inadequate. Police Commissioner Karl O'Callaghan labelled it the most biased parliamentary inquiry he had been involved in, prompting then premier Colin Barnett to call for Ms Quirk to step down, which she refused.

Ms Quirk tweeted not longer after Mr McGowan made the announcement that she wished her WA Labor colleagues good luck adding that they have the "privilege and honour to serve in the first McGowan cabinet".

Play Video New premier Mark McGowan says he regularly catches the train to avoid traffic congestion New premier Mark McGowan says he regularly catches the train to avoid traffic congestion

Kate Doust, member for the south metropolitan region, member for Albany Peter Watson and member for Thornlie Chris Tallentire also lost out on ministry positions after being in the shadow cabinet.

Ms Doust will be president or deputy president of the Legislative Council, Mr Watson will be Speaker for the Legislative Assembly, and Mr Tallentire will be one of six parliamentary secretaries.

A new cabinet secretary position has gone to member for Morley Amber-Jade Sanderson.Fran Logan will be a minister despite landing himself in hot water days before the state election when a video surfaced of him threatening companies working on Roe 8 with legal action if they sought compensation for broken contracts.

Mr Barnett last week demanded Mr Logan be denied a ministerial position but Labor gave no such assurance.

New Premier Mark McGowan said he hoped colleagues who missed out on a cabinet position wouldn't be too disappointed.

"There's always people who are disappointed in politics but the great thing is we're forming a government and they'll get the opportunity to participate in implementing our policies and doing good things for the state," he said before Labor's first caucus meeting on Wednesday.

He then congratulated his team after they applauded his arrival for almost a full minute.

"What's clear is we're going to need a bigger room," he quipped, given Labor is predicted to hold 41 seats of the 59-seat parliament.

He said his government would focus on creating jobs, getting WA's ailing finances back on track, and improving health, education, community safety and transport.

"From this point forward, the hard work begins," he said.

John Quigley, who was shadow attorney general and expects to continue that work, says his first priorities will be to lift the statute of limitations period for victims of child sexual abuse seeking compensation and 'no body no parole' laws for convicted murderers.

Portfolios will be allocated on Thursday.