Labor claims crushing WA election victory

Opposition Leader Zak Kirkup called Mr McGowan about two hours after polls closed on Saturday to formally concede defeat.

Results suggest the Liberals' nightmare scenario has become reality, with the party set to be reduced to just two MPs and lose their opposition status to the Nationals.

Mr Kirkup has lost his marginal electorate of Dawesville, becoming the first WA Liberal leader to lose his seat since the 1930s.

He reiterated that he would not seek re-election at a state or federal level.

"It is a loss that will be difficult to bear," he said in his concession speech.

"But in so doing we must remember that 2021 is not an end but a beginning. In so doing, we must remember that it is an obligation we all have to make sure that over the next four years, we do all we can to help rebuild this party."

Deputy leader Libby Mettam and David Honey appear set to retain their safe seats of Vasse and Cottesloe respectively.

But Labor is ahead in the blue-ribbon Liberal seat of Nedlands.

"This is a disaster, let's be honest about it," retiring former Liberal leader Mike Nahan told the ABC.

The ABC's electoral analyst Antony Green called the election for Labor with less than one per cent of the vote counted.

Labor's parliamentary majority could ultimately be the biggest held by any party in WA's history on the back of a double-digit swing.

Nationals leader Mia Davies is on track to become WA's opposition leader, with her party predicted to hold five lower house seats.

She said the next state parliament would be difficult for the opposition to manage but her party was up to the challenge.

Her colleague Vince Catania, a former Labor MP who defected to the Nationals in 2009, has not ruled out challenging Ms Davies for the leadership.

Cheers rang out across Labor's election-night function as results flashed up predicting gains in Kalgoorlie, Darling Range and Hillarys.

Deputy Premier Roger Cook said voters had rejected the Liberals' campaign against handing Labor too much control.

"People are recognising that Labor's a good government," he said.

"Mark McGowan is a great premier and has led a good government that takes responsible and careful decisions and doesn't act out of temper."

The scale of the Liberal defeat is certain to intensify calls for party reform amid concerns about the influence held by conservative powerbrokers.

"This will be a cleansing for the Liberal party and it will be up to us to get our act into gear," Dr Nahan told the ABC.

"Unfortunately we (have) very few seats to work with."

A call by the Liberals to open WA borders while the state continued to deal with COVID-19 had done "immense" political damage, Dr Nahan added.

Australian Associated Press