Australia claims it has uncovered a South Korean spy ring attempting to obtain trade secrets as the two nations negotiate on a free trade agreement.

The espionage case dates back to 2010 and relates to efforts by South Korea’s National Intelligence Service “to obtain sensitive information” on Australian trade with the help of the Yeon Kim, a senior Australian agricultural trade specialist, according to the Australian Security Intelligence Organization, Sydney Morning Herald reports.

Kim is appealing to overturn a decision by the ASIO to strip him of his security clearance, which means he has been effectively dismissed from his job in the Agriculture Department, reports Reuters.

Australian Foreign Minister Bob Carr refused to comment on details of the case, citing “matters of security intelligence,” but said the issue had caused no diplomatic tensions with Seoul and relations between the two countries remain robust.

Although South Korea engaged in what ASIO described as “inappropriate foreign interference” harmful to Australia’s interest, no South Korean diplomats were expelled over the incident.

The case became public after Australia’s Federal Court lifted secrecy orders surrounding the incident.