A Department of Home Affairs (DHA) contractor suspected of illegally sending classified documents to an unsecured location was allowed to continue working in the public service.
The man is alleged to have stripped the "classified" status from files relating to 500 departmental projects, before forwarding them to his personal email address to access at home.
A figure familiar with the "serious" breach of security protocols told the ABC the contractor removed the classification ratings from documents so his actions did not trigger an internal departmental alert system.
One of the man's former colleagues says he held a NV1 (negative vetting level 1) security clearance, which allowed him ongoing access to view secret documents, in addition to temporary, supervised access to top-secret information.
His unauthorised activity is believed to have taken place from as early as 2020 until the man's contract ceased in June 2021, and to have involved projects across the Home Affairs portfolio, including Australian Border Force data.
Senior figures within DHA are understood to have become aware of the breach in September last year when the organisation's cybersecurity unit detected the documents had been sent externally.
The contractor was then brought back for a meeting with the department's intelligence branch head who queried him over the breach of security protocols, resulting in him agreeing not to take on further projects with the department.
The Department of Home Affairs then referred the case to the Australian Government Security Vetting Agency (AGSVA), which is the central vetting agency for the Australian Government and conducts security clearance assessments.
The man was later hired for contract work with another large federal government department on project management, despite several former colleagues within DHA's intelligence branch declining to provide personal references.
'Strong integrity framework in place'
A Home Affairs spokesperson told the ABC it did not comment on individual matters, but added the department had "a strong integrity framework in place to detect, deter and disrupt this behaviour".
"Where inappropriate conduct occurs, including acting outside of procedures, the Department takes action in close cooperation with partner agencies including the Australian Federal Police (AFP) and the Australian Commission for Law Enforcement Integrity (ACLEI).
No formal intelligence breaches were recorded inside Home Affairs last year. However, the ABC has been unable to verify whether any departmental investigation has determined if the classified information was passed on to third parties.
ACLEI says it received 32 referrals from the Home Affairs portfolio for possible corruption between July 1 and December 22 last year.
Six of those incidents were investigated by the integrity body, with one being sent back to the department for further investigation.
Altering Commonwealth records without approval is a breach of the Commonwealth Crimes Act and a breach of the Department of Home Affairs' internal security instructions.
