AFP officers enter the Melbourne headquarters of the AWU in Spencer Street. Credit:Chris Hopkins "The application will be to object to the validity of the investigation and the warrants," the spokesman told AAP. The Commission said the raids were triggered after it received information that documents relevant to the investigation were being "concealed or destroyed" and sought authorisation from a magistrate for immediate AFP access to the documents. The commission's investigation, launched earlier this month, is examining whether the $100,000 donation was within the AWU's rules. The investigation came after a referral from Employment Minister Michaelia Cash in August. But Senator Cash said she did not order the raids and did not find out about them until they were already under way.

NSW Police raid the Sydney office of the AWU. Credit:Wolter Peeters "I found out as it unfolded on the television," she told a Senate estimates hearing. She says others in her office were informed shortly before she was, but insists none of her staff alerted anyone in the media. Asked if she had asked the Registered Organisations Commission to investigate how the media learned about the raids, she said: "They're an independent agency, so no I have not." Senator Cash was also asked whether she had referred any other matters to the Commission but she declined to answer, saying she would take it on notice.

Mr Shorten on Wednesday described the raids as "a political witch hunt". "Well, quite frankly, the use of 30 AFP officers to collect documents, which, as the union has said, all they had to do was bring up, was an amazing waste of money, but we understand what this is about," he said. "I have the greatest respect for the Australian Federal Police and its serving officers. What I don't respect is that the regulator, at the behest of the government, is conducting a political witch hunt designed to throw mud in the hope that some will stick." Late on Tuesday, AWU national secretary Daniel Walton labelled the raids "an extraordinary abuse of police resources" and part of an attempt to smear Mr Shorten. "We're extremely concerned about the actions of the Registered Organisations Commission and extremely concerned of the actions of the Turnbull government," he said.

In a statement, GetUp! said the dramatic police actions raised "concerning questions" and said the organisation handled the 2005 donation appropriately. "This is part of a pattern from this government trying to silence its critics or anyone who challenges it," GetUp! national director Paul Oosting said. Opposition employment spokesman Brendan O'Connor said: "It's clear from what has happened today that Malcolm Turnbull has intervened and has abused his position in power and abused the resources of the police to make an attack on the Leader of the Opposition." Mr O'Connor said the Registered Organisations Commission, re-established by the government after the double dissolution election, had used its "coercive powers" to deploy police and called on Mr Turnbull to explain his involvement. Mr Turnbull told reporters the union "has got questions to answer [and] Bill Shorten has questions to answer", and lashed Mr O'Connor's comments.

Loading "The police keep us safe from crime, safe from terrorism, and uphold the rule of law, and the AWU should comply with the law and when they have spokesmen like Mr O'Connor, [who] would prefer to defend the thugs and criminals in the CFMEU than stand up for the police that keep us safe, that shows you a lot about the values of the Labor Party and Bill Shorten." - with AAP