Federal government officials haven't been able to say whether they've investigated corruption allegations surrounding an offshore detention contractor which has links to Nauru's current and former presidents.
Pressed on revelations a government contractor has poured at least $761,000 into the parent company of a business linked to Nauru's president David Adeang, bureaucrats from Home Affairs insisted they'd done their due diligence.
"The department undertakes its own independent checking in relation to those matters," First Assistant Secretary for offshore programs Ben Biddington told a parliamentary inquiry on Tuesday.
Asked whether the department had investigated allegations the company paid kickbacks to Mr Adeang and other Nauruan officials, Mr Biddington said he would review the government's paperwork and report back.
The immigration deal came to light when an unreleased report by Australia's financial crimes watchdog was entered into the public record. Greens senator David Shoebridge read sections of the AUSTRAC report into Hansard in late 2025.
Official figures released late on Monday revealed fresh information about Australian taxpayer dollars flowing to a business linked to Mr Adeang.
Under the offshore immigration program, a private company called MTC Australia has been paid to provide accommodation, maintenance and security on Nauru.
Water delivery services have been subcontracted to a firm called Chazaq Corporation Limited.
Chazaq owns another business, LRC Car Rentals, which is linked to Mr Adeang and the former president's wife.
Senator Shoebridge put questions about the offshore immigration contract to the Department of Home Affairs.
"As at 31 October 2025, the total value of payments to MTC Australia for the Chazaq subcontract was $761,370," the department said in its response, published before the Tuesday hearing.
Pressed on the revelations, MTC Australia executives told the Senate inquiry they had followed procedures set down by Home Affairs, including requiring Chazaq to provide a signed conflict of interest disclosure.
Senator Shoebridge accused the government of presiding over a "corrupt" arrangement covered by a cloak of secrecy.
"Organised cruelty can only be done through corrupt arrangements, as we're seeing on Nauru," he told the hearing.
Government officials disputed his comments.
The Nauruan High Commission was contacted for comment.
In November 2025, Senator Shoebridge used parliamentary privilege to accuse Nauru's president of siphoning off millions of dollars of Australian taxpayer money.
He told the Senate that AUSTRAC had formed a suspicion of corruption and money laundering against Mr Adeang, based on the rapid movement of large sums of money from LRC Car Rentals.
Former president Lionel Aingimea and his wife Jacinta were also named in the report, which was produced some time before September 2022, Senator Shoebridge told federal parliament.
After a series of revelations about offshore detention contracts, the government ordered an independent review of the migration system.
In response, it agreed to improve its subcontractor approval processes and bolster due diligence for providers.
The hearing also heard eight people had now been deported to Nauru under a secretive deal with the tiny Pacific nation, stemming from a High Court decision which threw Australia's system of indefinite immigration detention into chaos.
The agreement involves Australia paying $400 million in up-front costs and $70 million annually to send former immigration detainees to Nauru.
Officials from Home Affairs took questions about the deal on notice, saying they had not prepared to be pressed on the deportation arrangements as they didn't believe they fell under the inquiry's purview.