Levels as high as 307,000 becquerels of caesium per kilogram of soil have been detected 60 kilometres from the damaged nuclear plant, a non-governmental organization said on Wednesday. The level is three times over the levels set by the government, according to environmentalist group Friends of the Earth Japan and a local citizens' group.

The Japanese government's legal limit is 10,000 becquerels per kilogram. Tomoya Yamauchi, professor and radiation expert at Kobe University, who was in charge of the survey, examined soil samples collected on September 14 from five locations in the city.

According to Yamauchi, the whole area was so contaminated that it would be necessary to remove not only the topsoil but also the road surfaces, pavement, roofs and concrete walls. Since the Fukushima Daiichi Nuclear Power Station was crippled by the March 11 earthquake and tsunami, it has been leaking radioactive material into the environment. In April, the government declared a no-go zone 20 kilometres around the plant.

The development comes days after Japan lifted evacuation advisories for five areas between 20-30 kilometres from the nuclear plant and as it looks to convince tens of thousands of people that it is safe to return home.

Evacuation in progress

"We are urging the central and local governments to have children and expecting mothers evacuated from the areas," said Takeshi Sakagami, a member of Citizens Against Fukushima Aging Nuclear Power Plants, according to an AFP report.

Last Friday the Japanese government said it would lift five "evacuation preparation" zones between 20 and 30 kilometres from the plant, where residents were not forced to evacuate but were told to be ready to do so in the event of further setbacks at the crippled plant.

On Tuesday a nuclear reactor in south western Japan was automatically shut down due to a problem with its cooling system, but operator Kyushu Electric said no abnormalities had been detected.

Agencies: dpa, AFP (mj)

Editor: Sarah Berning