It was one of a succession of phone intercepts, totalling more than 30 minutes of profanity-laden conversation between Mr Lomax, fellow CFMEU workers and builders and contractors, that dominated Wednesday's hearings.

One recording called into question Mr Lomax's claim he attended a Milin Builders' site in Turner on April 21 only to respond to traffic management issues, not because the company had refused to sign an EBA.

Another indicated that the site visit, which involved up to five branch officials, had, contrary to union claims, been premeditated and was meant to disrupt a concrete pour.

Mr Lomax was also heard telling contractors that non-union workers would have to be removed from union-dominated projects and warning some contractors, but not others, of an imminent CFMEU crackdown on concreters in April and May.

Intercepts also revealed the union worked closely with contractors who had signed CFMEU EBAs to keep non-unionised companies, which undercut their mutually agreed rates, out of the commercial construction sector.

Mark Walker, a Canberra bricklaying contractor, texted Mr Lomax on April 8 asking "Hey mate, can you check out which grub of a bricklayer is doing the childcare building for cobul in gungahlin they will be laying bricks there next week".

The two spoke on April 13 about GeoCon allegedly using non-CFMEU EBA bricklayers on one of its sites.

Mr Lomax told Mr Walker he would be giving the errant contractor a union enterprise agreement document. He said: "He told me he's getting four dollars a block."

Mr Walker said: "What a f---wit".

Canberra CFMEU officials have repeatedly said they did not know of allegations against Kivalu until he admitted at commission hearings in July that he accepted inappropriate payments from builders, which led to him being charged with two counts of blackmail.

Cleaning company boss Adrian Maretta thanked Mr Lomax, a former Canberra Raiders star, for his help on a membership issue on April 10, saying if "Fihi" Kivalu had been on the case he "would have hit me up for f---in' five grand by now".

Mr Lomax said: "No. No, no, like, I'll – I'll – I'll – I'm not interested in that bro."

Under cross-examination by counsel assisting the commission Jeremy Stoljar, Mr Lomax said he had been "deeply shocked" by the corruption claim.

Mr Stoljar said: "Deeply shocked? You said you were not interested [in discussing the claim]. Where did you express surprise? Wasn't it widely known Fihi was hitting people up for money?"

Mr Lomax said: "Not at all, but I had forgotten about it [the conversation]. I meant I'm not interested in taking money off the bugger [Mr Maretta]."

He did not report the claims about Mr Kivalu to his superiors at the time.

A later conversation was reported to the union management.

Mr Maretta said the non-union worker had been recruited off Gumtree to fill a vacancy that had come up by chance.

Mr Lomax said the worker needed to be a member of the CFMEU if he were to stay on the site.

An agreement was later reached for Mr Maretta to pay for "half a breakfast table", possibly at a fundraiser for the union's charitable trust, to put the issue to bed.

Mr Lomax said: "I've heard you say that you will donate so we'll, I'll keep you to that, all right?"

Mr Maretta said: "Hundred per cent. No dramas."

Mr Lomax apologised to the commission's stenographers for their exposure to the "foul language" in the recordings at the end of his testimony.

Commissioner Dyson Heydon said they had "heard worse".

ACT CFMEU branch secretary Dean Hall is expected to take the stand when the hearing continues on Thursday.

Correction: An earlier version of this story named the wrong person whose phone calls were intercepted. They were between Mr Lomax, fellow CFMEU workers and builders and contractors.