A Border Force spokesperson did say that, in general, the federal customs and immigration agency is not aware of any legal proceedings involving travellers and relies on notifications from law enforcement agencies to prevent departures.

The Independent Commission Against Corruption (ICAC) on Monday revealed that Sydney migration agent Yueming 'Monica' Hao had left Australia via a flight to Dubai on August 19 after receiving a summons on July 7 to appear at a hearing.

Mr Maguire admitted to ICAC last year that he was part of a "scam" whereby Riverina businesses were paid cash to employ Chinese nationals on regional work visas who rarely, if ever, turned up to work.

The businesses had the cost of the workers' wages reimbursed by Mr Maguire's scheme, plus cash payments on top, while the Chinese nationals gained a pathway to citizenship.

According to documents and testimony at ICAC, the scheme's visa paperwork was allegedly handled by Ms Hao, who had a database of wealthy individuals in China who could afford to pay a fee of up to $150,000 for a fake job placement, which was split between herself, Mr Maguire, the host employer and another go-between, Maggie Wang.

In response to questions about Ms Hao's departure from Australia during COVID-19 restrictions on travel, an Australian Border Force spokesperson said the agency did not comment on individual cases.

"The ABF does not have visibility of the personal obligations of individuals in relation to legal proceedings," they said.

"Outbound travel restrictions were implemented as a health response to slow the spread of COVID-19, on the advice of the Australian Health Protection Principal Committee.

"Outbound travel exemption requests are assessed against a set criteria as outlined on our website and generally are approved where the criteria is met.

"It is important to note that Australia's travel restrictions are a health measure, and are not a mechanism intended to prevent travel for law enforcement purposes."

In response to questions from NSW Labor Senator Kristina Keneally at hearings in October last year and in April, senior executives from ABF and Australian Federal Police confirmed that the agencies were investigating Mr Maguire's visa scheme.

Senator Keneally said the government had "some serious questions" to answer over Ms Hao being allowed to leave Australia.

"How on earth did Australian Border Force give a witness in an ICAC inquiry into a Liberal Party cash-for-visa scandal, run by Gladys Berejiklian's secret boyfriend Daryl Maguire, permission to leave the country? It's either absolute incompetence or something more sinister," Senator Keneally said.

"Did the Minister for Home Affairs or her office know? Did the Prime Minister's office know?

In other news

The ABF declined to answer questions around whether Ms Hao was a person of interest in a the Federal Police investigation into Mr Maguire's visa scheme.

"Any further restrictions to travel rely on law enforcement alerts from the relevant jurisdiction," an ABF spokesperson said.

"The ABF is able to prevent an individual from departing Australia where a law enforcement body has put in place an appropriate alert."

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