Mr Kan, on a tour of areas wrecked by the disaster, promised to do everything possible to help the communities.

Japan is set to mark a month since the disaster with local meetings, but there are no national events planned.

The tsunami, triggered by a 9.0-magnitude earthquake, killed thousands and left many more homeless.

Some villages on the north-east coast of Honshu island were largely destroyed.

The disaster also severely damaged a nuclear plant, which is still causing huge problems for the authorities.

Mr Kan told survivors in the city of Ishinomaki: "The government will give all its strength to work with you. We will never abandon you."

He said the government will "work as fast as possible" to house 150,000 people still living in emergency shelters - some 17,000 of them in Ishinomaki.

The PM also tried to reassure survivors that the fishing industry, which many in the area rely on for their livelihoods, will resume as soon as possible.