China and South Korea rebuffed on Sunday Japan's calls for more reasonable restrictions on imports of food and other products that could be contaminated with radiation after last month's nuclear disaster, showing the difficulty Japan will face in restoring trust in its products.

Trade ministers from China and South Korea also told their Japanese counterpart they hope Japan can quickly repair its supply chain, which was damaged after last month's earthquake and tsunami, as shortages of Japanese manufactured goods will impact the global economy.

I asked China and South Korea to make sure there is a scientific basis for restrictions on our imports, Japanese Trade Minister Banri Kaieda told reporters after a summit meeting.

South Korea's response was that they have to place importance on peoples' safety. China also stressed the importance of food products.

Kaieda met with Chinese Commerce Minister Chen Deming and South Korean Trade Minister Kim Jong-hoon as Japan grapples with its worst crisis since World War Two.

A 9.0 magnitude earthquake and a tsunami towering more than 10 meters battered its northeast coast on March 11, leaving nearly 28,000 dead or missing and triggering radiation leaks at a nuclear power plant.

The government estimates the material damage alone could top $300 billion, making it by far the world's costliest natural disaster.

Several countries have restricted food imports from Japan over radiation fears. China has banned imports of some Japanese food and agricultural products. South Korea banned food imports from four areas of Japan affected by the nuclear crisis until radiation concerns ease.

Shortages of electricity and important parts that manufacturers need to make their goods suggest there will be deep and long-running output disruptions that could production in other countries.

Much of what Japan sends to China are crucial high-tech inputs in its auto, machinery and electronics sectors. Assembled into final products, these are later exported by China.

In South Korea's case, the country competes with Japan in exports of cars, semiconductors and electronics.

(Reporting by Stanley White; Editing by Daniel Magnowski)

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