Former Wagga Wagga MP Daryl Maguie has had to answer questions over his role in a scheme where Chinese citizens acquired work visas on the basis of sham employment with mostly Riverina-based businesses.

These ghost employees rarely showed up for work, reimbursed the employer for their own wages, and the business received substantial sums of money in kickbacks, as did Mr Maguire, ICAC has heard.

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Mr Rorris said there had been enough examples of work visa schemes being rorted to beg the question why immigration authorities hasn't put a stop to it.

He said the highest levels of government should explain what they knew.

"There should be an immediate audit and open investigation involving industry, union representatives and government into the visa worker and training programs to expose these rorts and provide some confidence and integrity to the system," Mr Rorris said.

He said Prime Minister Scott Morrison, Home Affairs Minister Peter Dutton and NSW Premier Berejiklian should explain what they knew about repeated visa scams.

Mr Rorris went so far as to claim there may be Federal Government "elements" who enabled these visa scheme rorts. The Department of Home Affairs was contacted for comment on Thursday but had not responded by deadline.

"We have long suspected that there were elements of the Federal Government that were effectively operating as a protection racket for these scams that exploit foreign workers, compromise our immigration system and ultimately deprive local workers of jobs," Mr Rorris said.

"There is a new phrase for politicians turning a blind eye - it's 'I don't need to know about that bit'.

"I am sure there are many people in our community who now believe that the call for international workers by some politicians and bosses has nothing to do with a labour shortage but an exploitation shortage."

In response to Mercury questions, the Department of Home Affairs sent a statement saying it had "zero tolerance" of scams.

Department secretary Mike Pezzullo would later tell a Senate committee on Monday that Home Affairs had not launched an investigation into Mr Maguire, although it was "examining" matters raised in ICAC.

"The Department and ABF have no tolerance for the exploitation of Australia's migration system, and work with partner government agencies to investigate any identified instances of visa and migration fraud," the statement said.

"It is unlawful for persons to ask for, receive, offer or provide a benefit in exchange for a sponsored work visa arrangement. This applies to temporary work sponsored and permanent skilled employer nominated visas.

"Anyone who is aware of an individual, business or employer who may be involved in or facilitating visa fraud should report this to Border Watch."

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