The ban on shipping rice from a district in the city of Fukushima due to high levels of radioactive cesium shows the need to amend the two-phase test currently performed to check the grain for radiation, farm minister Michihiko Kano indicated Friday.

The contaminated rice was not tested by the government, which only examines samples. The high level of cesium was detected only when a farmer took it to a local agriclutural cooperative to be tested on Monday.

"The shipment ban is an unfortunate result. We will need to review the radioactive contamination test system for next year," he said, adding that details will be discussed with the health ministry and Fukushima Prefecture.