The investigation will be completed before September 30, 2011, one month after the previous deadline, since the case was "special" and "complicated," according to a statement posted on the ministry's website.
China launched an anti-subsidy investigation on the imports of EU-made potato starch on August 30, 2010 at the request of the China Starch Industry Association.
It is China's first-ever anti-subsidy probe into imports from the EU.
The probe focused on whether the EU members subsidized exports of potato starch to China, and if so to what extent the subsidies had harmed domestic industries.