The complaints were detailed in response to counsel assisting's submission in October, which alleged the Construction, Forestry, Mining and Energy Union used safety issues to apply "inappropriate industrial pressure to ACT construction industry figures".

Restricting rights of entry to building sites and increasing penalties imposed for breaches were among a number of reform recommendations identified by counsel assisting Jeremy Stoljar, SC.

The CFMEU submission, lodged by Slater and Gordon Lawyers on Friday morning, claimed commission procedures were unfair and there was insufficient evidence to suggest any laws had been broken.

The union's lawyers said attempts to establish cartel behaviour had "failed spectacularly" and a lack of evidence was supplemented by inferences and innuendo.

"The evidence relied upon to elevate campaigning for better wages and conditions to cartel behaviour amounted to no more than the type of inexact proofs, indirect references and speculation that would carry no weight in any court," they said.

"The union rejects any suggestion that the ACT branch or its current officials have acted unlawfully or inappropriately. Counsel assisting have simply not made out the case theory on the evidence before the commission."

The union's lawyers said counsel assisting had questioned how the union dealt with rumours about misconduct, claiming this was outside the terms of reference.

"To attack the CFMEU for not acting upon vague rumours in the absence of any evidence of a complaint is no more than an attempt to smelt base metals into gold."

The commission held hearings into the conduct of Canberra union officials in July, September and October, in both the ACT and Sydney.

The visit resulted in a number of high-profile arrests, including official John Lomax and former organiser Halafihi "Fihi" Kivalu.

Allegations of blackmail were formally dropped against Mr Lomax, while Mr Kivalu was committed to stand trial in the ACT Supreme Court on two blackmail charges.

A third man, Tuungafasi Manase, has maintained his plea of not guilty to perjury before the commission with a hearing set for May next year.

The commission barristers did not recommend any criminal charges against ACT officials as the matters were before the courts.

They also refrained from submitting findings about alleged anti-competitive behaviour as the Australian Competition and Consumer Commission was already probing allegations of cartel conduct

"The ACCC is better placed than this commission to evaluate the extent to which conduct of the kind referred to in these submissions is permissible under the existing statutory regime," the submission said..

The CFMEU has also claimed delays and the location of the hearings caused significant inconvenience for ACT based officials.

"The manner in which extensive material was provided to the union in July and the time frames set for response were onerous," the submission said.

"More importantly, the allegations against the union were allowed to stand unanswered for many months. This caused unnecessary damage to the union's reputation.

"The inquiry commenced with a bang and a dramatic opening in July and ended with a whimper with circumspect submissions in October."