Cases of contaminated vegetables, tea, milk, seafood and water have already stoked anxiety after the world's worst nuclear crisis since Chernobyl (1986), despite assurances from officials that the levels are not dangerous.

Aeon Co said it had sold the contaminated beef at a store in Tokyo and at more than dozen stores in the surrounding area, as radiation continued to spill from the Fukushima nuclear power plant four months after the March 11 earthquake and tsunami.

Aeon, which competes with top retail group Seven & I Holdings, said in a statement that cattle from Fukushima prefecture were given animal feed originating from rice straw that exceeded the government's limits for radioactive cesium.

Japan is now likely to ban shipments of beef, hugely popular in Japan, from around Fukushima, a cabinet minister said on Sunday. It was not immediately clear what had delayed such a move, which is likely to inflame criticism that the government has been too slow in its response to the crisis.

Reuters