Health Services Union national secretary Kathy Jackson’s federal court battle with the union over her slush fund took a sensational turn this week when she claimed the union had “committed a fraud on the court".

The HSU is pursuing Jackson for almost $250,000 paid into a slush fund, as well as legal fees. Jackson told the Royal Commission into trade unions on Thursday that the money was transferred legally to conduct union political business, although she conceded that the conduct might not have met the standards of the public.