"The Registered Organisations Commission procured the contract initially anticipating that proceedings would be concluded in December 2017," a spokesman said. "The AWU has sought and obtained adjournments and the hearing is presently listed to take place at the end of this month." The AWU is seeking to quash the commission's investigation into donations it made to the activist group GetUp! in 2006 - when Opposition Leader Bill Shorten was the union's boss - amid claims it did not follow proper procedures. The union is seeking to prove there was an "improper political purpose" behind the investigation. Jobs Minister Michaelia Cash referred the allegations to the Registered Organisations Commission after a media report about the Labor leader's role. The commission subsequently obtained search warrants for raids on AWU offices in Sydney and Melbourne in October last year. However the Australian Federal Police raids backfired spectacularly for Senator Cash after it emerged that one of her staffers - media adviser David de Garis - tipped off the media that they were about to occur.

He quit his job but did not publicly disclose who leaked the information to him, saying only it was a "media source". The AFP subsequently launched an investigation into the source of the leak, which still has not concluded. The AWU's case is due to go to trial on March 28. However it could be delayed - raising the prospect of further cost blowouts for taxpayers - while the AFP investigation continues. The AFP has agreed not to hand over any of the AWU documents it seized until the Federal Court case concludes. ACTU boss Sally McManus and AWU national secretary Daniel Walton after AFP raided their offices. Credit:Chris Hopkins The union wants the court to declare that the commission's investigation and search warrants were invalid. If the court rules in the union's favour it will be another embarrassing blow for Senator Cash and badly damage the commission's credibility.