All I can find in the article is the following [emphasis mine]:
Another AI breach is under investigation after a rogue agent accessed public information on a state government web application.
The NSW premier's department on Friday said it had been informed by OpenAI, the tech company behind ChatGPT, that one of its models accessed a National Parks and Wildlife Service web application containing historical information and data on fires in NSW.
No mention of "hacking" or breaking in to systems -- just some sort of word-association-insinuation. Did anything actually happen? Sounds like fuss about nothing again.
The LLM agent's process is suggested to have sought out information beyond the bounds of the task defined by its operator -- which is a recurring pattern to criticise about LLM reliability/safety/usefullness, but there's no suggestion anything nefarious happened from the perspective of NSW government.
If something significant did happen, please post a decent article about it.