The construction union's national secretary has admitted the CFMEU doesn't get it right all the time, but it strongly rejects the re-establishment of a building industry watchdog.
Addressing an at times fiery Senate hearing into legislation to reinstate the Australian Building and Construction Commission, Dave Noonan told senators on Friday the union has no tolerance for corruption.
Asked to respond to government and industry representatives claims of "thuggery", he said: "We don't get it right all the time".
"Sometimes people say and do stupid things, but the laws that are enforced are enforced by a regulator (Fair Work Building & Construction) whose sole purpose in life really is to attack workers and unions."
Coalition senators Bridget McKenzie and Linda Reynolds used their questions to ask Mr Noonan about cases of CFMEU officials - Luke Collier and Bradley Upton - before the courts.
The separate cases include accusations of intimidation towards FWBC inspectors and allegations of swearing on a building site, they said.
Just before the end of the hearing, Mr Noonan asked committee chair, Senator McKenzie if she had any questions on the bill itself instead of "scary, sweary stuff".
"I came here to talk about the bill," he said. "We've done this bill to death, Mr Noonan. No new evidence has been presented by anybody," she replied, adding they had read the union's formal submission and it is the third committee looking into the legislation, which has already been blocked by parliament.
Representatives from the Master Builders Association, Australian Industry Group and Chamber of Commerce and Industry all called for the legislation to pass, citing the findings of the Heydon royal commission into union corruption.
The chamber's Richard Calver told the committee the Australian Building and Construction Commission would help foster greater productivity and improved culture in the sector.
"The industry would create buildings without industrial disruption and without escalating costs," he said.
"Certainly it would have far-reaching implications on the industry."
On Friday, ministers conceded a Senate vote on the legislation was unlikely before May 11 - the deadline for calling a double-dissolution election.
Instead the government's priority for the last sitting week of parliament before the May 10 budget will be its changes to the way Australians vote for the Senate.
"This will take all of the usually-available government time in the Senate and more," Finance Minister Mathias Cormann said.
Employment Minister Michaelia Cash too conceded Senate voting changes would take precedence, but said the ABCC remained a "fundamental priority" for the government.