Seven staff at bankrupt Ssangyong Motors research institute will face trial accused of industrial espionage.

They were accused on Wednesday of supplying information on key diesel and hybrid technology to Ssangyong's parent company, SAIC of China which has a 51% stake in Ssangyong.

The technology is alleged to include details on engines, transmission systems and a control system for a hybrid car which Ssangyong has developed with state money.

Prosecutors have been investigating the case for more than three years following a complaint by Ssangyong's union accusing SAIC Motor Corp of stealing core technology on hybrid cars. The technology is claimed to be state registered and cannot be shared without government approval despite SAIC having a majority stake in Ssangyong.

"Even if Ssangyong and SAIC were legally merged, the two companies remained as independent entities in that transferring the technology without a legitimate contract is illegal," said a spokesman at the prosecutors' office.

This isn't the first time South Korea's prosecutors have acted over alleged industrial espionage in China. In 2007 five former and current employees of Kia Motors were accused of selling car assembly secrets to China and last year prosecutors arrested a former engineer with South Korea's LG Electronics for stealing and leaking flat-screen TV technology to China.