The CFMEU demanded one of Queensland's most senior public servants take direct calls about complaints as minor as toilet air freshener cans not being registered as hazardous worksite chemicals.
Queensland's Commission of Inquiry into the CFMEU this week heard claims the union had a "hotline" to the mobile phone of then Office of Industrial Relations director-general Peter McKay.
Union officials refused to use a public 1-300 phone number to report workplace safety concerns and said "we only call the top dog", Commissioner Stuart Wood heard.
Mr McKay, who is now director-general of Queensland's Department of Trade, Employment and Training, appeared as a witness at the inquiry on Thursday.
Upon taking the workplace safety role, Mr McKay said he told staff "we are never going to repeat the situation" where a single person was the point of contact for the union.
Mr McKay agreed having one person talk directly to the union about safety complaints risked regulator capture and allegations of preferential treatment.
"You ended up doing this yourself, the very thing you said you shouldn't do," Commissioner Wood said.
Mr McKay responded: "I made it clear all I was doing was passing on the message. My email said because it comes from me it should be given no greater priority."
Mr McKay said he told CFMEU leaders that calling him would just cause delays in responding to complaints.
Yet the CFMEU continued to call Mr McKay's mobile with complaints every week.
"They were almost never serious issues," Mr McKay said.
Counsel assisting Dimitri Ternovski asked if he ever got complaints from the CFMEU about toilet disinfectant spray cans in the workplace.
"You had more than 900 people working under you and you are receiving calls about Glen 20 not being on the chemical register," Mr Ternovski said.
Mr McKay said he did not force the CFMEU to use the 1-300 number because the union would have complained to ministers in the then-Labor government.
"(Former state union leader) Michael Ravbar does have the ear of government," he said.
Mr McKay claimed he was confronted in person by Mr Ravbar at a coffee shop in a public service office in February 2024 after he did not take union calls during a meeting.
"He continued to move towards me. I was in a position where I'm backed against a wall by these two people dressed head-to-toe in CFMEU gear."
According to Mr McKay, Mr Ravbar said the workplace safety organisation was incompetent and people should be sacked.
"(The tone) was angry, aggressive. There were a lot of f-bombs," Mr McKay said.
The inquiry is due to continue its public hearings from April 21.
