The Ministry of Commerce has issued a notice ensuring that grain and grain product supplies maybe provided to Hong Kong, but it also warned of penalties for those who diverted such food shipments to other markets.

Wheat, corn, rice and flour made from these grains could only be sold to Hong Kong and violators would have their export licenses suspended. The licenses would only be available to suppliers who had signed agreements with designated Hong Kong counter-parties.

"The relevant authority should issue a license strictly according to the quota allocated by the government and note on the license that the export is only to Hong Kong with no transshipment is allowed," said the notice.

Hong Kong importers had to keep clear inventory and sales records that tracked food imported from mainland, said the notice.

Controls on food exports started early this year, when the government imposed a temporary quota on the export of wheat, corn and rice products to guarantee domestic supplies.