Fair Work Australia (FWA) general manager Bernadette O'Neill is standing by her organisation's report on the Health Services Union's national office and former union boss Craig Thomson.
Mr Thomson accused FWA, in a speech to parliament on Monday, of conducting a biased investigation and failing to interview key witnesses who would back his innocence.
Ms O'Neill says it would be "inappropriate" to comment on Mr Thomson's speech.
"The report of the investigation into the Health Services Union national office prepared by my delegate, Mr Terry Nassios, speaks for itself," she said in a statement today.
"These matters will be the subject of legal proceedings in the
Federal Court of Australia and that is the appropriate forum in which to test the evidence and findings set out in the investigation report."
Ms O'Neill said solicitors had been instructed to prepare documents for the Federal Court case, which will include 156 alleged contraventions against Mr Thomson identified in the investigation report.
THOMSON: ENOUGH ALREADY
Earlier embattled federal MP Craig Thomson told the media that it should let nine investigations and pending court cases into the HSU take their course without getting further into the "gutter".
Mr Thomson's comments came a day after the privileges committee began looking at whether he misled parliament in his hour-long statement on Monday in contrast to the findings of a Fair Work Australia investigation report released earlier in May.
The committee is also investigating a leak to the media, which suggested that it wanted more specific details from the coalition on how it believed Mr Thomson misled the parliament and its rejection of a proposal to advertise for witnesses to come forward.
The HSU and Mr Thomson, who led the union from 2002 to his election as a Labor MP in 2007, face a series of police investigations, parliamentary inquiries and multiple Federal Court cases relating to maladministration and misuse of members' funds.
The MP for Dobell was stood aside from the Labor caucus in April when Prime Minister Julia Gillard declared that a "line had been crossed", but he denies any wrongdoing and plans to defend any future court action.
Mr Thomson told reporters in Canberra on Thursday it was time to let all of the processes take their course.
"We have two police investigations, we had the AEC (electoral commission) on two occasions ... there's an ongoing investigation by the Victorian police, we've also had it referred to privileges and a couple of other committees," he said.
"What I'm here to say is guys, enough is enough."
Mr Thomson acknowledged the issues need to be pursued.
"But I think nine investigations probably does it," he said.
The NSW MP also took aim at the Nine Network's A Current Affair program which has reportedly interviewed a former prostitute.
The FWA report, tabled in parliament, found that Mr Thomson misused around $6000 on escort services when he was general secretary of the HSU - a claim he denies.
"Frankly this is journalism at its worst ... let's not descend any further into the gutter," he said.
ACA executive producer Grant Williams said he had a statutory declaration from the ex-prostitute who was working in Sydney during the mid-2000s.
"At this stage of the game I can categorically state we haven't paid anyone and we haven't broadcast anything, but we have recorded an interview and we have taken a stat dec," he said.
Mr Thomson said he and his staff continued to get hate mail.
"Is this about trying to push someone to the brink?" he said.
PROCESS 'MIUST TAKE ITS COURSE'
Leader of the House Anthony Albanese told reporters all of the processes should be allowed to take their course without interference.
"This isn't a game, this is not a joke ... the coalition need to have a good look at the way they are operating," Mr Albanese said.
He said the intimidation of MPs or committees was a crime attracting "serious penalties".
Privileges committee chairwoman and Labor MP Yvette D'Ath said her committee specifically discussed the importance of members not disclosing matters while it was considering the issue.
"I am extremely disappointed that this disclosure has occurred," she said.
Deputy chairman, Liberal MP Patrick Secker, said he supported Ms D'Ath's decision to pursue the leak, which could constitute a contempt of parliament.
