Mandatory imports of rice are piling up in Japanese government warehouses, entailing storage costs of JPY17bn a year, Japan's farm ministry has said.

By WTO agreement, Japan imports 682,000 tons of rice a year but only 100,000 tons of that goes on the market. Tokyo blames a lack of consumer interest in foreign rice. "But we hope to come up with some measures to whet demand," said a ministry spokesman.

With a 490% tariff on imported rice foreign importers accuse Japan of protectionism. "In our view Japan does not provide fair market access," said Bob Cummings at the US Rice Federation.