Senator Michaelia Cash claims “media source” tipped her office on AWU raids

Senator Michaelia Cash has denied being politically motivated to discredit and embarrass Opposition Leader Bill Shorten by referring alleged union wrongdoings for investigation.

The cabinet minister was accused of lying in the Federal Court on Friday, during heated questioning by Australian Workers' Union lawyer Caryn van Proctor about what she had wanted to achieve in asking a watchdog to look into decade-old donations.

The union is taking action against the Registered Organisations Commission, claiming federal police raids on AWU offices in Sydney and Melbourne in connection with the inquiry were unlawful.

Despite knowing she couldn’t direct the independent ROC to investigate, Senator Cash said says she felt it was incumbent upon her to ensure the watchdog was aware of potential wrongdoings she read about in a 2017 news report.

It was alleged the AWU may have failed to get proper authorisation for a $100,000 donation to activist organisation GetUp in 2006, when Mr Shorten was the union's national secretary and on GetUp's board.

Senator Cash also referred a $25,000 donation to Mr Shorten's election campaign.

In a repetitive courtroom exchange, she denied being pleased or displeased when finding out two months later an investigation had begun, but also denied she had neutral feelings or no view at all.

She was eventually pressed by Justice Mordecai Bromberg to admit her view "would have been to wonder what the outcome will be".

She gave similar repetitive responses when asked what she had hoped to achieve.

"Am I to take it as meaning you had no interest (in the outcome)?" Justice Bromberg asked.

"At the end of the day, no," she replied.

But Ms van Proctor argued Senator Cash was pleased when the investigation began, that she thought it would harm Mr Shorten's reputation and could discredit both he and the Labor Party.

The union alleges Senator Cash wanted to politically discredit or harm Mr Shorten and Labor and the ROC took steps to accommodate that outcome.

“You wanted the ROC to investigate Mr Shorten and the AWU,” Ms van Proctor said. “No, I did not,” Senator Cash replied.

“That's just not true. You're not giving true and accurate evidence,” Ms van Proctor fired back, to further denials by Senator Cash.

Earlier, Senator Cash said the first she heard of the raids was seeing them on television.

A number of people with ties to her office have been outed as having prior knowledge of the raids.

They include Mark Lee, a media adviser on secondment to the commission who had been offered a job in Senator Cash's office.

He was said to have passed on details to Senator Cash's then chief of staff Ben Davies, who passed on the information to her media adviser David de Garis, who conspired with former justice minister Michael Keenan's then media adviser Michael Tetlow to contact journalists.

All four later left their positions.

The hearing continues next week.