Union whistleblower Kathy Jackson has complained of being ambushed by evidence showing a $50,000 payment to her ex-husband.
Union boss Kathy Jackson withdrew $50,000 from her union slush fund and gave it to her former husband, a corruption inquiry has heard.
Ms Jackson, the 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.
Ms Jackson told the commission she felt "ambushed" over the evidence and asked for an adjournment to get legal representation - something she has not had previously.
The commission heard the $50,000 was drawn from a union slush fund, the National Health Development Account (NHDA), over which Ms Jackson had sole control, on March 24, 2009.
On the same day, a bank cheque for $50,000 was made out to Ms Jackson's former husband and fellow HSU official, Jeff Jackson.
The money was for issues Mr Jackson was facing in his Victorian HSU branch, Ms Jackson said.
At a previous appearance at the commission in June, Ms Jackson said she could not recall what the $50,000 withdrawal was for.
The commission has heard Ms Jackson transferred $284,000 from a union account to the NHDA between 2004 and 2010, but 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.
Ms Jackson also admitted previous evidence she gave to the commission about the establishment of the NHDA was wrong.
At an 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 that 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 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 told the commission a letter outlining the payment was "packaged up" as reimbursement to avoid embarrassment to Peter MacCallum's board.
Ms Jackson came to prominence for blowing the whistle on corrupt former HSU general secretary Michael Williamson, who is now in jail.
The inquiry continues.