LABOR’S primary vote was on track to crash below 25 per cent last night in the WA Senate re-run, as support for the Greens and the Palmer United Party surged.

After a train wreck of a campaign by the ALP, the result will spark bitter recriminations in Labor leader Bill Shorten’s demoralised caucus.

There were fears that as few as one in five WA voters had supported the ALP.

The Liberal Party was also on track for a beating, possibly losing its third Senate spot at an election for the first time in 25 years.

The fate of Labor Senator Louise Pratt hung in the balance last night, but there were hopes she could hang on with the support of strong preferences from the Greens.

The Liberals were still hopeful Linda Reynolds could make it to Canberra in the party’s third position. Insiders said postal votes might get her over the line.

But Liberal support was bleeding to Clive Palmer’s PUP party, which had the biggest swing of the night with a 7.5 per cent increase.

While it was too early to call the final result, the outcome was likely to deliver a win for two Liberal Senators, Greens Senator Scott Ludlam, Labor’s Joe Bullock and Clive Palmer’s PUP candidate Dio Wang.

Senator Pratt and Ms Reynolds were in the hunt for the final spot.

FULL COVERAGE:

■ OPINION: Bill Shorten and Tony Abbott let election chances go

■ Defiant Pratt fights odds

■ Ludlam praises campaign effort

■ Palmer’s big spend ‘worth it’

■ Roll up, roll up to the Senate circus

■ Joe Spagnolo: Party over for voters

With the no-show from fatigued voters forced back to the polls as high as 15 per cent, the low voter turnout favoured the Greens.

About 93 per cent of West Australians turned up to vote at the September poll.

The Australian Electoral Commission said that postal votes and pre-polls were up on last year.

“It’s looking fantastic at this stage,’’ Greens leader Christine Milne said last night. “We’re going to take it right up to Tony Abbott.”

Senator Ludlam said the result was a blow to the major parties. “The only way to compete with the major party funding was with people power,” he said.

The WA Senate by-election followed an Australian Electoral Commission bungle in September in which 1370 votes went missing, throwing the original result into doubt.

As the polls closed yesterday, former Labor minister Stephen Smith said the Liberals were at risk of getting only two senators, rather than three.

“If the Liberals were only to get two senators out of a six Senate race, that would be the first time in a quarter of a century it would have occurred,” he said.

Perth Federal MP and Labor stalwart Alannah MacTiernan said the swing against the party made it clear it was time to change how it chose candidates. She said the party had to stop putting union heavies before genuine talent.

“The Greens are beating us in some of our booths. Booths I would have won comprehensively six months ago,” she said.

Departing for his North Asia trade tour, Prime Minister Tony Abbott, who accused Mr Palmer of trying to buy seats in Parliament, urged voters to send a message on the Senate’s blocking of the abolition of the mining tax and the carbon tax.

“This election in Western Australia does matter. It is important for your future. It is important for the future of our country,’’ Mr Abbott said.

West Australians couldn’t escape Mr Palmer in the past month, with the eccentric minerals boss drowning the state in a big-spending advertising barrage.

Media analysts believe the PUP spent 10 times the amount of the major parties on TV advertisements urging voters to “Stick It Up Em’’ and describing the Australian Electoral Commission as “mongrels”.

But yesterday, Mr Palmer and his two thumbs-up salute were nowhere to be seen.

Mr Wang had no idea where his leader was.

“I’m not sure, to be honest. He might be here. I only met him once this week to be honest,” he said.

Mr Palmer’s media minder Andrew Crook said his boss was not in WA.

“He’s left WA, that’s correct,” Mr Crook said.

But Mr Palmer himself claimed to be in Albany, 420km from Perth, when he spoke to The Sunday Times on his mobile phone yesterday.

On Friday, Mr Palmer suggested he was in Kalgoorlie.

But while there were photographs of his candidates campaigning in the Goldfields, there were no images released of the businessman.

Advertising monitoring firm Ebiquity estimated PUP had spent $500,000 on TV ads, but Liberal sources suggested it could be up to $6 million overall.