The ALP and Liberals are both hopeful of winning the final seat in WA’s re-run senate election, despite a voter swing against them.

Labor, the Australian Greens and the Palmer United Party (PUP) are each likely to have picked up one seat in WA’s re-run senate election, while the Liberals have seized two seats – but it is the elusive sixth spot that has many on edge.

If the government’s third candidate, Linda Reynolds, does not win, it will be the worst result for the Liberals in the WA senate for 25 years.

But if Labor’s Louise Pratt loses, it will be a blow to the ALP, which has criticised the federal government’s refusal to release its Commission of Audit report before the WA poll, which reportedly contains recommendations for savage budget cuts.

So far, 89.72 per cent of polling places have counted first preferences, showing a 5.49 per cent swing against the Liberals and a 4.83 per cent swing against Labor.

Phil Diak from the Australian Electoral Commission told AAP it appeared voter turnout was at about 85 per cent, with more than one million votes already counted.

Counting was limited on Sunday but will resume at 11am (WST) on Monday, he said.

Prime Minister Tony Abbott dismissed the swing against his party, noting candidates opposed to the carbon and mining taxes had “performed very strongly”.

“There was absolutely nothing in this vote yesterday to suggest that the voters have suddenly decided they love the carbon or mining tax,” he said in Tokyo.

But Greens Senator Scott Ludlam, who appears to have retained his seat, said the result was a “damning indictment” of a government that had only been in power for seven months.

Senator Ludlam also took a swipe at Labor, saying they were “internally divided”.

Labor was forced to defend pre-selecting Joe Bullock after reports of his 1996 conviction for assault, his record of voting for the Liberal Party and comments that Labor could not be trusted and was full of mad members.

Foreign Minister Julie Bishop told ABC television that Labor’s low vote of just under 22 per cent was a “real slap in the face” for Opposition Leader Bill Shorten.

She added that the Coalition and PUP could have a “constructive relationship”.

Mr Shorten said the major parties suffered from people’s frustration in having to go back to the polls, but said the result was certainly not an endorsement for the government.

Meanwhile, the Australian Greens have renewed a push for a cap on electoral expenditure to stop wealthy people spending millions of dollars on advertising for their candidates.

Senator Ludlam criticised PUP for its estimated $6 million advertising blitz rather than presenting strong policies except to promise to address GST redistributions.

“He (Clive Palmer) kept his candidates almost completely out of sight and he’s running on a platform effectively of tax avoidance for his various mining businesses,” Senator Ludlam said.

“I think Mr Palmer’s going to find it very difficult to hold his party together, quite frankly.”