Labor is on track to win Saturday’s state election in Western Australia, according to a Galaxy poll released on Sunday.

The poll, commissioned by the Sunday Times, shows Labor has a 54% to 46% lead over the Liberal-National alliance on a two-party preferred basis.

According to the poll, Labor has picked up a larger than expected swing that would result in Mark McGowan claiming a convincing win over the premier, Colin Barnett.

The managing director of Galaxy, David Briggs, said Labor’s primary vote was at 40% and it would have to rely on preferences from the 24% of voters who support the minor parties.

He said Labor would likely achieve the usual strong preference flow from Green voters but he said they could also pick up pick close to 50% of preferences from One Nation supporters.

If the predicted 11% swing is uniform, Labor could pick up Perth, Forrestfield, Belmont, Swan Hills, Morley, Balcatta, Mount Lawley, Bicton, Kalamunda, Joondalup, Southern River and Wanneroo.

Labor would also win the notionally Liberal-held seats of Collie-Preston and West Swan.

Barnett said on Sunday the Coalition party was still in the game because of undecided voters.

“I’m a little bit disappointed but I think it confirms what most polls have indicated, and while there’s been a great deal of variability within the polls, it’s clear that the Labor party has been in front,” Barnett told reporters. “There’s still the best part of a week to go and a large number of voters, maybe 15-20% have yet to decide how they’re going to vote so we’re still in this game.”

Barnett said of McGowan: “Mark’s OK, he works hard, but I tell you what, Western Australia is headed for mediocrity.”

The premier said the Labor campaign was being massively funded by the unions, helping the party outspend the Liberals on advertising five-to-one.

“Almost every second ad on television and radio is a union ad having a go at me or having a go at the Liberal party,” he said. “Probably two-thirds of a McGowan cabinet will be recent union officials.”

The campaign enters its final week on Sunday. The One Nation leader, Pauline Hanson, is expected in WA for the final week.

Hanson took heart from the Galaxy poll that shows One Nation on 9%.

“I do believe we will win seats in the upper house, especially as the Libs are preferencing us before the Nats and Labor,” she told ABC TV on Sunday.

She also called the former One Nation candidate Ray Gould, who quit over the party’s preference deal with the Liberals, a Labor stooge for his public outburst.

“He has come across to One Nation as a disgruntled person,” she said.

The former Labor prime minister Bob Hawke campaigned with McGowan on Saturday, while the foreign affairs minister, Julie Bishop, attended a Liberal rally with Barnett.