An Australian man who recently returned to the country after living overseas has been charged with supplying sensitive information to foreign intelligence agents.
Fifty-five-year-old IT specialist Alexander Csergo was arrested by Australian federal police shortly after he landed back in Sydney.
The authorities say that two years ago he was approached by two foreign spies.
They allegedly offered to pay him for national security information.
In a statement, the Australian Federal Police (AFP) said an individual claiming to be from a think tank contacted Mr Csergo via social media while he was overseas and arranged for him to meet two representatives.
Court documents show that Mr Csergo is believed to have met the pair, who went by the names "Ken" and "Evelyn", in the Chinese city of Shanghai, though police have not specified which country is accused of trying to gather illicit information.
Mr Csergo was offered money to obtain information about Australian defence, economic and national security arrangements, plus matters relating to other countries, the AFP's statement said, adding: "Espionage and foreign interference pose a serious threat to Australia's sovereignty, security and integrity of our national institutions."
Mr Csergo is only the second Australian to be charged under anti-spying laws that were put in place five years ago.
The Australian authorities are appealing for anyone else who met with Ken and Evelyn to also come forward.
Mr Csergo appeared at Parramatta Children's Court in New South Wales by video link. The matter has been adjourned until Monday 17 April.
The maximum penalty is for the count of reckless foreign interference, for which Mr Csergo is facing is 15 years' imprisonment.