Court clears Senator Cash over union raids

Police raids on union offices in Melbourne and Sydney were not made to embarrass then-opposition leader Bill Shorten, a judge has ruled.

Federal Court Justice Mordecai Bromberg on Friday rejected the Australian Workers' Union's claims that the raids in October 2017 by the federal government's union watchdog, the Registered Organisations Commission, were made to "embarrass or politically harm" Mr Shorten.

Officers were looking for evidence linked to alleged decade-old donations from the AWU to activist organisation GetUp!, potentially funnelled into political campaigns used to target the Liberal Party in 2006 and 2007.

Justice Bromberg cleared Liberal Senator Michaelia Cash, who referred the allegations of possible misconduct to the ROC, of wrongdoing.

"I have concluded that the evidence before the court does not establish that the decision made to conduct the investigation was made for the improper purpose contended for by the AWU," he told the court.

There was a win for the union though, with the judge finding the commissioner's decision to raid the offices was invalid.

He said the raids were based on a "suspicion", which was not reasonable grounds for an investigation.

"The commissioner did not proceed reasonably in forming the opinion or state of satisfactory he was required," Justice Bromberg said, noting the raid was "affected by jurisdictional error and invalid".

The Federal Court will hold a hearing in November to determine whether this makes the search warrants invalid.