Some former residents from the 20-kilometre (12-mile) no-go zone around Japan's crippled Fukushima Daiichi nuclear power plant will be allowed to visit their homes, according to reports.

A government task force has decided to ease restrictions in three of the 11 municipalities within the 20km-radius restriction zone, media reports said. But activities will be limited, with none of the 14,000 people who lived in the re-opened areas allowed to stay overnight.

A massive earthquake and tsunami on March 11 last year knocked out the plant's cooling systems and sparked reactor meltdowns, forcing some 78,000 people in the 20km ring to flee under officials orders.

It was the worst nuclear crisis since the 1986 Chernobyl disaster.

"The government will work as one to repair the environment in order to help residents come home as soon as possible," Prime Minister Yoshihiko Noda, who chairs the task force, was quoted as saying.

The task of restoring communities even in lightly contaminated zones is complicated, with high costs and the logistical difficulty of deciding where to store soil contaminated with radioactive caesium.

The three municipalities to be reopened in April are the cities of Tamura and Minamisoma and Kawauchi village.

Entry into places where radiation levels exceed 50 millisieverts per year remains banned except for authorised brief home visits in exceptional circumstances.

In places with radiation levels between 20 and 50 millisieverts per year, residents are advised to visit their homes only for pressing reasons and refrain from outdoor activities.

And where radiation levels are 20 millisieverts per year or less, preparations will be made for lifting an evacuation order. Hospitals and commercial facilities can prepare to reopen and factories can resume operations.

In December, Japan announced it had achieved a stable state of "cold shutdown" at the Fukushima plant after months of clean-up operations, but the public has remained sceptical about the safety of the plant.

Tens of thousands of people have been also forced from home beyond the the no-go zone, including some areas in a wider 30-kilometre radius where people were first told to stay indoors and later urged to leave.

The process of fully restoring the areas around the crippled Fukushima plant is expected to take decades.