China's senior foreign trade ministry official Jiang Fan warned earlier today [Friday] that Japan is "seriously impairing" bilateral trade ties between the countries by insisting on tough new inspections of frozen spinach imports from China.

"These inspections have gone beyond accepted standards and constitute discrimination against Chinese products," Fan is quoted by Reuters: "These measures are seriously impairing development of bilateral trade."

Japan says it is merely enacting food safety regulation after it revealed last month that it had discovered high levels of pesticides in some frozen spinach imports. Fen insisted however: "China firmly opposes any protectionist and discriminatory measures taken in the guise of food safety."

The move by Japan is just one more twist in a long running trade dispute between the countries, highlighted last year when Japan imposed "safeguard" curbs on Chinese imports of shiitake mushrooms, leeks and straw to protect its domestic farmers. At the time China retaliated by imposing 100% punitive tariffs on Japan's cars, mobile telephones and air conditioners, although in this latest row officials did not mention retaliation.