TOKYO  - Japan found the first case of rice with radioactive materials far exceeding a government-set level for a preliminary test of pre-harvested crop, requiring thorough inspection of the rice to be harvested from the region, the farm ministry said late on Friday.

A rice field is seen in Soma, about 40 km (25 miles) north of the tsunami-crippled Fukushima Daiichi nuclear power plant, in Fukushima prefecture, September 10, 2011. REUTERS/Kim Kyung-Hoon

The ministry said radioactive caesium of 500 becquerels per kg was found in a sample of the pre-harvested rice in Nihonmatsu city, in Fukushima Prefecture, 56 km (35 miles) west of the Fukushima Daiichi nuclear plant which was crippled by the March 11 earthquake and tsunami, triggering the world's worst nuclear disaster in 25 years.

The ministry said the Fukushima Prefecture will expand the inspection spots nearly ten-fold to around 300 areas.

It is the first case in Japan of rice containing radioactive caesium exceeding 200 becquerels per kg, a level which requires further thorough testing of the area for the harvested rice.

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