Polls have opened in Western Australia with Premier Mark McGowan tipped to lead Labor to a victory that could wipe out much of the Liberal opposition.
Voting commenced at more than 700 polling places at 8am local time on Saturday, with the polls set to close at 6pm.
More than 750,000 people had already voted prior to polling day.
With Labor expected to comfortably win a second term, the focus will be on how many seats the already-depleted Liberals manage to save.
A Newspoll published in The Weekend Australian newspaper has Labor leading the Liberals 66 to 34 per cent on a two-party preferred basis.
It would reduce the Liberals to as few as three seats if replicated at the ballot box.
Opposition Leader Zak Kirkup is at risk of becoming the first WA Liberal leader to lose his seat since the 1930s.
The 34-year-old holds the seat of Dawesville by a margin of just 0.8 per cent and has vowed to quit politics if he is voted out.
Such a result would likely spell disaster for other Liberal MPs vying to save their seats.
It would also suggest Mr Kirkup's decision to concede defeat a fortnight before polling day and warn against giving Labor "total control" was a tactical failure.
Mr Kirkup defended the strategy while campaigning in Dawesville on election eve, saying he was simply levelling with voters.
"We asked West Australians to think about what cost it would be to them and their communities if Labor does get elected with too much power," he said.
"And I'm very, very sure that as people go to the polls that is something they will think about."
Mr McGowan visited the marginal Labor seat of Joondalup for his final pitch to voters, saying the government will remain in the sensible centre if re-elected.
"Our government has shown over the last four years that we're stable, reasonable, sensible people that put in place policies that protect the jobs and health of West Australians," he said.
"If we're re-elected, that will continue."
A Labor source said the party had been expecting Mr Kirkup to survive in Dawesville based on its internal polling.
Labor is confident of adding seats but there is little chance it will gain control of the upper house due to the extra weighting given to regional votes.
