BEIJING - China has extended an anti-dumping probe on coated white cardboard imported from the United States, the Ministry of Commerce said Friday.

The probe, which was launched on Nov 18, 2011, will be extended for another six months to May 18, 2013 due to the complexity of the case, the ministry said.

It initiated the probe after domestic paper producers, on Oct 8, 2011, submitted a formal application accusing US companies of dumping the product in China.

Coated white cardboard is mainly used to make packages for tobacco, medicines, cosmetics, foods and liquid.