Political analyst David Black says National Party preferences should be enough to secure the Liberals a sixth WA Senate seat.

The Liberal party is likely to win a third seat in the re-run West Australian Senate election, a political analyst predicts, based on key preferences.

While counting continues, Greens candidate Scott Ludlam has undoubtedly retained his seat, the top two Liberal candidates appear home and hosed, Labor has secured one seat and Palmer United Party is looking comfortable with one seat.

But in the battle between Liberal and Labor for the sixth seat, the latter could lose out, says David Black, history and politics professor at Curtin University.

“I assume the Greens preferences will find their way fairly soon to Labor, but they may not have that many preferences because they may have to use up most of their vote in order to get their quota,” Professor Black told AAP on Monday.

“I would have thought on the figures I’ve seen so far, that unless Labor pick up some significant chunks from other places, then the Liberals will probably win the final sixth seat because the Liberals will get the National Party preferences for a start.

“The Nationals have got enough to make a bit of a difference.”

Professor Black said there would be severe recriminations within the Labor party over ordering of candidates on its Senate ticket.

If the order had been reversed – with Louise Pratt ahead of union stalwart Joe Bullock – it would have had a much better chance of winning a second seat, he said.

The Liberals had strong candidates and if the party didn’t win the sixth seat, it would only be because of competition from the Palmer United Party, Professor Black said.

Member for Perth and former Labor state minister Alannah MacTiernan said the re-run poll had been a salutary experience for both major parties.

But there was no papering over the fact it was not going well for Labor, she said.

Ms MacTiernan said she was not the only one in the party who had been arguing for reform for many years, “particularly concentrations of power blocs, a small number of people who wield a great deal of power and that’s not healthy in any system”.

“We’ve got to open this up so that we are attractive to a broad range of people, and can go out there and build a constituency,” she told ABC radio.

“We’ve got to reflect the community, we’ve got to show leadership.

“We’ve got to have candidates who can win votes for us.”

Defence Minister David Johnston, who was first on the Liberal ticket, said it was a shame Labor’s Mark Bishop was retiring as he was “their best performer”.

Senator Johnston also noted – as many had – the absence of Mr Bullock and Ms Pratt from Labor’s how to vote cards.

“It’s just bizarre what goes on inside the Labor party,” he told ABC radio.