CITIC Resources Holdings Limited has begun court proceedings against the operator of a bonded warehouse at Qingdao port at the centre of an investigation into metals financing fraud.

CITIC Resources said last month it had been unable to secure around 120,000 tonnes of alumina, although it had title to 223,270 tonnes of alumina and 7,486 tonnes of copper stored at the port pending payment by and delivery to buyers.

The company is requiring the port operator to confirm its ownership, and to release and deliver all alumina and copper, to the group or to offer compensation, it said in a filing to the Hong Kong stock exchange.

CITIC Resources is the commodities trading unit of China's biggest and oldest state-owned financial conglomerate company, Citic Group Corp.

The group is not able to accurately assess the impact on the Group's alumina and copper stored at Qingdao port or on the Group itself until the investigation is complete, it said on Tuesday.