Credit cards issued to National Union of Workers' officials in NSW were used to buy sex toys and pay for more than $600 in food and drinks from "breastaraunt" chain Hooters, documents obtained by the trade union royal commission show.

Credit card records obtained by The Royal Commission into Trade Union Governance and Corruption suggest union members' funds were used to pay for the sex toys charged to the credit card of the union's former NSW branch secretary, Derrick Belan.

The purchases were among $39,000 in charges on Mr Belan's credit card from the Catch of the Day website. The card was used to buy Tiffany and Co jewellery, perfume, iPads, cameras, Lego toys, electric blankets, manchester and bed linen, cutlery sets,rugs, skateboards, kitchen appliances, sunglasses, children's toys, Easter eggs, and make-up and beauty care products.

Under cross-examination in the commission this week, Mr Belan denied using his union credit card to make purchases from the website. His niece, Danielle O'Brien, admitted to making purchases through the website.

The documents show Mr Belan's credit card was used in 2012 to buy a number of sex toys, including an  "Ophoria XL V-RING", totalling $144. 

Transaction records show $629 in food and beverage from Hooters restaurant in Penrith was charged to the union credit card of Mr Belan's brother, Nick.     

Questioned if he had charged the entertainment to his work credit card, Nick Belan told the commission ​"yes, that could have been me, yes".

He could not recall if he had been on union business  "I could have paid it and then paid it back, or something like that," he said.

Documents show $2,271.70 in fees for dating websites were also charged to Derrick Belan's union card. 

ACTU secretary, Dave Oliver, has threatened to suspend the union's NSW branch amid anger from union leaders that the exposure of alleged corruption by the branch's former officials has damaged the union movement and undermined its attack on the commission.

The union's national secretary, Tim Kennedy, said the union intended to take civil action against Derrick Belan, his brother, and Ms O'Brien, to try to retrieve the hundred of thousands of dollars in union funds that were allegedly misspent. 

During her evidence, Ms O'Brien admitted to a number of purchases using union credit cards. She also admitted to diverting union funds into her personal bank account.

She said officials commented on the extent of her shopping. "Everybody said something because I have a problem," she said. "I just want to buy things I can't help it."

Mr Belan used his union credit card to pay for a tattoo of his mother and late father, Frank Belan, who preceded him as the union's NSW secretary. The union card was also used to fund a four-day cruise, which he said was a "present" from Ms O'Brien and his brother, when they both worked at the union.

Derrick Belan, who has been staying in a psychiatric hospital, apologised to union members for the embarrassment and humiliation caused by the scandal but denied any impropriety. He said he used to ask Ms O'Brien to deduct the cost of some credit card purchases from his wages, while other charges made on holiday were work-related.