Threats made by the CFMEU boss John Setka have been referred to police by the federal employment minister.
The peak union body in Victoria has refused to condemn threats made by a CFMEU boss at a rally as federal Labor distances itself from the controversy.
CFMEU state secretary John Setka told a Melbourne rally on Tuesday the union was going to expose Australian Building and Construction Commission inspectors and make their children "ashamed of who their parents are".
"Let me give a dire warning to them ABCC inspectors, be careful what you do. You're out there to destroy our lives," he warned.
But Victorian Trades Hall Council Secretary Luke Hilakari did not condemn the comments, instead saying ABCC inspectors made it "hard for union officials to save workers' lives".
"If you'd been to the funerals these blokes have, you'd be more concerned about the ABCC running around like the government's ideological attack dog and endangering lives, than some off-handed comments at a rally," Mr Hilakari said.
Federal employment minister Michaelia Cash has referred the "intimidating behaviour" of the CFMEU boss to federal police and Victoria Police.
She told parliament during question time in the Senate on Wednesday that "violent thug" Mr Setka had reached a "whole new low".
Because of the "extremely serious nature" of the threats" she had referred them to authorities to investigate.
Federal Labor was quick to condemn Mr Setka's threat and distance the party from the union.
Opposition Leader Bill Shorten said "that's not the way to advance your cause".
"I repudiate in the strongest terms what was said," he said on Wednesday.
Federal Labor frontbencher Anthony Albanese said the police referral was "appropriate".
"The comments are offensive. I completely repudiate them," he said.
Victoria Police have confirmed it is looking into the issue and will consult with Australian Federal Police.
The ABCC was established by the Howard government in 2005 to tackle illegal behaviour on construction sites.
Then the Gillard Labor government scrapped it in 2012, replacing it with Fair Work Building and Construction.
When the coalition regained government it reinstated the ABCC, causing anger in the construction workers union.