Julia Gillard enabled the incorporation of a union slush fund from which her then boyfriend later stole hundreds of thousands of dollars by formally denying to authorities that it was a trade union organisation.

A newly released document confirms that Ms Gillard wrote to the WA Corporate Affairs Commission stating the fund, the Australian Workplace Reform Association, was not a trade union organisation. Her assertion came in mid-1992, after the commission initially rejected the association's incorporation because ''it might be a trade union and therefore ineligible''. The document also confirms that Ms Gillard, then a salaried partner with Slater and Gordon, drafted the rules for the association - without opening a formal file, without consulting the senior partners and without taking advice from expert lawyers within the firm.

The revelations contradict Ms Gillard's claims at media conferences and in Parliament that she played a limited role in the formation of the association, from which Bruce Wilson and his crony Ralph Blewitt later misappropriated more than $400,000.

Asked by the Deputy Opposition Leader, Julie Bishop, on Monday whether she had written vouching for the bona fides of the association, Ms Gillard told Parliament: ''The claim has been made but no correspondence has ever been produced.''