China's Ministry of Commerce (MOC) said Wednesday it has extended by six months a one-year anti-dumping investigation into methanol imports from Saudi Arabia, Malaysia, Indonesia and New Zealand.

Originally scheduled to be completed Wednesday, the investigation is now scheduled to finish December 24.

"The case is quite special and complicated" and so more time is required, the MOC said in a brief statement on its website that did not elaborate.

The MOC announced the investigation on June 24, 2009, saying it would examine the scale of the alleged dumping and the extent of damage to the domestic industry.

Methanol, also known as methyl alcohol, is used to produce chemical products like plastics, paint, construction materials and windshield washer fluid.