SYDNEY, Sept 24 (Reuters) - Australia said on Thursday an OpenAI agent breached a government health data portal in June, gaining unauthorised access to files, in what could be the first known instance of an AI agent hacking a government ‌website.

The breach is one of the highest-profile incidents of AI agents accessing external systems outside the United States, coming on top of several ‌recent breaches globally by rogue AI agents that have alarmed governments and companies.

Prime Minister Anthony Albanese said the OpenAI agent gained unauthorised access to the medical statistics portal of Medicare, Australia's universal ​health insurance programme, while conducting research on public medical spending.

"Evidence currently available is there is no broader compromise to the ... network. Nonetheless, this situation is obviously unacceptable," Albanese told reporters on Wednesday in New York, where he is attending the UN General Assembly.

Investigations continue and Australia has voiced its "extreme concern about this incident" to OpenAI CEO Sam Altman, Albanese said, adding that he was deeply disappointed by the company's delay in notifying the government.  "It took until September 10 before there was any notification at all," Albanese ‌said, adding that the investigation would also examine why government ⁠systems had failed to detect the breach in the first place.

He also warned that three other government health-related websites may have been impacted by the OpenAI agent's activity, but did not confirm that had occurred.

In a statement, OpenAI said its "review found no ⁠evidence of patient records being accessed."

It added that it "identified activity involving several Australian government websites and services as our models attempted to look up answers ...