Evidence is surfacing about labour hire being embroiled in union payoffs, the employment minister says, as the CFMEU is being investigated for alleged coercion.
The construction arm of the CFMEU has been placed into administration after allegations of criminal conduct and organised crime links on job sites.
The Fair Work Ombudsman has 42 ongoing investigations into the commercial building and construction industry, involving most branches of the CFMEU, its officials and employers.
"A significant proportion of the information received by the FWO has involved alleged coercive behaviour by the CFMEU and its officials," Acting Fair Work Ombudsman Michael Campbell told AAP.
Bad behaviour had been associated with labour hire in the construction industry, Employment Minister Murray Watt said.
"What is becoming clearer to me as the minister is the really central role that labour hire firms have played in some of the criminal activity that we've seen around the industry," he told reporters in Melbourne on Wednesday.
The issue was a key focus of a meeting the minister convened with union and industry officials.
Senator Watt said he had been briefed by the Australian Federal Police commissioner and was confident they are investigating "a number of these issues that have come to light and others that haven't even been in the public domain".
While Victoria has been the epicentre of alleged criminal wrongdoing, there were serious allegations across NSW and Queensland construction union branches, Senator Watt said.
CFMEU officials face large fines and jail time if they frustrate or obstruct the administration process.
The National Building Industry Group Unions, which comprises of 23 union leaders representing over 250,000 workers, criticised the forced administration of the CFMEU, saying it had been denied natural justice with no court findings.
The group will hold a "trade unions for democracy summit" on December 9 following what it calls a groundswell of support against the forced administration.
The summit will consider creating an alternative union body to advocate for workers, a political campaign and funding union-aligned electoral candidates.
Australian Council of Trade Unions secretary Sally McManus said only six per cent of the labour movement "if you're generous" was up in arms against the peak body for supporting the administration.
Most unionists supported stamping out violence, intimidation and corruption, she said when asked if there was a split between unions over the course of action taken against the CFMEU.
Opposition workplace relations spokeswoman Michaelia Cash called for the federal government to close a loophole that allows unions to pay fines imposed on individual officials or delegates.
