Union whistleblower Kathy Jackson says she was “ambushed” by evidence showing she gave $50,000 from a union slush fund to her ex-husband and has sought to halt a corruption inquiry while she gets legal advice.

Ms Jackson, the now national secretary of the Health Services Union (HSU), was confronted with a bank withdrawal slip for $50,000 bearing her signature in new evidence presented on Wednesday at the Royal Commission into Trade Union Governance and Corruption.

• ‘We didn’t steal from workers’: Jackson
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A bank cheque for the same amount was made out to her former husband, HSU official Jeff Jackson, on the same day.

In her previous appearance at the commission in June, Ms Jackson testified she could not recall what the March, 2009 withdrawal of $50,000 had been for.

After seeing the cheque on Wednesday she said she now remembered, prompting counsel assisting the inquiry Jeremy Stoljar SC to question her credibility.

“Are you saying that you had simply forgotten on the 19th of June that you had caused your ex-husband to be paid $50,000?” Mr Stoljar asked.

“That’s not credible evidence, is it Ms Jackson?”

Ms Jackson replied: “Well I think it’s credible evidence.”

The money was paid to help in a “fight” Mr Jackson was involved in with his own HSU branch, she said.

Kathy Jackson speaks to media after leaving the inquiry. Photo: AAP

Ms Jackson also admitted previous evidence she gave to the commission about the establishment of the slush fund, the National Health Development Account (NHDA), when she was secretary of a Victorian HSU branch, was wrong.

At her appearance in June, Ms Jackson said the NHDA was set up with a “windfall” $250,000 payment made by the Peter MacCallum Cancer Institute as a penalty after the union began legal action to recover underpaid wages for the institute’s employees.

Ms Jackson testified research workers received a settlement for outstanding entitlements worth “millions of dollars” and the institute, which is in Melbourne, paid the penalty to avoid legal action threatened by the union.

However, on Wednesday the commission heard workers did not receive back pay after the union settled the dispute with the institute and no legal action was ever instigated.

Documents also showed the Peter MacCallum Cancer Institute paid the HSU $250,000 as reimbursement for union funds spent on the case, including the wages of officials and legal advice.

Ms Jackson said the money was still a windfall for the union and not members’ money.

She said a letter describing the payment as a reimbursement was written to avoid embarrassment to Peter MacCallum’s board for having made the underpayment error.

The commission has heard Ms Jackson transferred $284,000 from a union account to the NHDA between 2004 and 2010.

Ms Jackson said she was authorised to make the transfers and use NHDA funds at her discretion.

She did not declare the funds in her income tax statements, she said.

“I just want to make it clear that the immense pressure that’s been on me and my family has been appalling.”

Two hours into the day’s proceedings Ms Jackson complained to Commissioner Dyson Heydon that she had no notice that she was going to be “attacked” by Mr Stoljar and accused of giving false evidence.

She said she had not had the chance to review the evidence put before her.

“I’ve been ambushed,” she said.

“I came here in good faith.”

Ms Jackson said she would apply through the commission for legal representation – something she has not had previously.

Ms Jackson’s actions as a union whistleblower helped expose corrupt HSU general secretary Michael Williamson, who was jailed in March.

• HSU boss Michael Williamson gets at least five years jail
• Disgraced HSU boss Craig Thompson gets 12 months jail

On Wednesday she told Commissioner Heydon she thought the inquiry’s focus was on the treatment of union whistleblowers.

Commissioner Heydon replied the inquiry into the HSU was not limited to that matter.

Ms Jackson criticised media coverage of the commission.

“I just want to make it clear that the immense pressure that’s been on me and my family has been appalling,” she said.

The inquiry will resume on August 25.

– AAP