Dermot Peverill from United Voice told the Queensland Parliament committee inquiry he spoke to three workers this week who were employed as contract cleaners.

“They’re working ordinary hours for their primary employer, a large cleaning contractor, who said, ‘We know you can only work 20 hours. We’ll now employ you under corporate structure B and corporate structure C and we’ll allow you to work additional hours but you’ll get half your award rate. And if you say anything about it, particularly to your union, you’ll no longer have a job’, he told the inquiry.

“Those employers are very sophisticated. They look at the legislation… and they look for those back doors.

“That’s the level of sophistication, and to combat that takes a great degree of precision in taking [an] application to a Federal Circuit Court.”

He added that “education will never be the remedy” given that migrant workers are the “most vulnerable people in the state”.

“They are vulnerable for a reason. Many are from non-English speaking backgrounds,” Mr Peverill said.

“United Voice, along with other unions ... has dedicated significant resources to try and protect those entitlements. But for those people, through no fault of their own, education will never be the remedy.”

Giri Sivaraman, principal lawyer for Maurice Blackburn Lawyers, told the inquiry that awareness of employment rights among migrant workers was “not that high”.

“When you come into Australia, you get told don’t bring any plants, food, drugs or other products - but you’re not told what your rate of pay should be. There’s no education in terms of employment rates,” Mr Sivaraman said.

“Because it’s a migrant workforce they’re much more vulnerable and very, very scared about speaking up.

“People call [me] up and then they get cold feet - they’re too scared. [They’ll say] ‘I don’t want to speak up, the law is this big unfriendly thing that I don’t understand, I’m not going to proceed with this.”

Shannon Fogarty from the Communications, Electrical and Plumbing Union revealed she had assisted a worker on a temporary 457 visa who was employed using a complex company structure, designed to exploit his lack of knowledge of employment law.

She told the inquiry the man was paid through an ABN on seemingly double the rate of pay, knowing he could only legally work a maximum of 20 hours a week - but then they tried to claw the extra money back shortly before he was due to return to his home country.

“Six months out from his return to his home country, they sent him a bill for all that money, saying, ‘Oh we just found out that there was an issue with your visa and you weren’t meant to be working'," Ms Fogarty said.

“They sent him a bill for the entire period he was working on an ABN [even though] they’d set up this system. And then they used it against him when he said, ‘Well, I obviously can’t pay that back.’

“[They said] we’re going to tell the Department of Home Affairs that this happened and get [you] sent back and because it’s such a legally technical area, [he said] am I going to be able to get back home? What’s going to happen?

“He’s not the only one. They’re setting up really specific systems and gentlemen’s agreements - even with students - saying they won’t put it in writing, and then going back to get that extra money off them six months before they leave.”

Ms Fogarty said the exploitative practices had even spread to trades such as plumbing.

“They’re setting up these systems to abuse the status of these workers in an industry where I previously hadn’t seen it before. That’s the business model they’re operating off,” she said.

During the inquiry’s afternoon session, it emerged that the Transport Workers’ Union does not have an enterprise bargaining agreement.

In a pointed exchange with TWU secretary Peter Biagini, deputy chair of the committee Jann Stuckey asked if the union’s Queensland branch had a publicly registered EBA.

“Do we have a publicly registered EBA? No, we don’t,” he replied.

Ms Stuckey asked: “Does that mean you have a private agreement with staff?”

Mr Biagini: “All our people are on salary, very flexible arrangement (sic) and there’s no need for an enterprise agreement.”

Ms Stuckey: “I find that difficult to fathom given that unions are saying we need EBAs to stop some of this wage theft.”

Mr Biagini: "We don’t say that at all."

"We don’t say that you necessarily need an enterprise agreement," he said.

"If a company wants to pay good wages, they don’t need an enterprise (sic). We normally need an enterprise agreement to get them on good wages, but if they’ve already got good wages

"…If they’ve got a living wage, that’s fine. Enterprise bargaining doesn’t seem to deliver that for many operators because they’re competing. A union doesn’t have to compete… They’re all salaried. Very good salaries.”