The operator of the crippled Fukushima nuclear plant on Friday offered the Japanese government a controlling stake in return for a huge cash injection that would prevent it going under, media reported.

Tokyo Electric Power (TEPCO) submitted a restructuring plan to the government that will allow for the defacto nationalisation of the company in return for a $12 billion payment, reports said.

The utility needs the money to pay the vast clean-up bills from the accident at Fukushima, when reactors were sent into meltdown after last year's tsunami struck.

It also faces colossal compensation claims from hundreds of thousands of people affected by the worst nuclear accident in a quarter of a century.

A company spokesman confirmed a plan to turn the company around had been submitted to the government, but refused to give details of its contents.

"This is an important step as we continue to swiftly and appropriately compensate people who have been affected (by the nuclear accident)," the spokesman told AFP, adding specifics would be revealed once the plan had been approved by government.

Local media said TEPCO has asked the government to inject one trillion yen ($12 billion) of capital, with the company offering a stake of up to two-thirds in return.

The firm will also seek permission from the government to raise household electricity rates by 10 percent from July, while vowing to make 3.3 trillion yen in cost savings over the next decade, Jiji Press said.

Trade and Industry Minister Yukio Edano, whose brief covers the nation's power industry, is expected to approve the restructuring plan in early May, local media reported.

The plant, which lies about 220 kilometres (135 miles) northeast of Tokyo, was hit by meltdowns and explosions triggered by Japan's massive earthquake and tsunami in March last year.

The government said last week that Kazuhiko Shimokobe, a 64-year-old lawyer, will become TEPCO's new chairman, adding that the personnel change will be endorsed at a shareholders' meeting scheduled for June.

The government hopes Shimokobe will take the lead in turning around the utility -- one of the world's largest -- as it compensates people and companies affected by the disaster and decommissions the four crippled reactors.

Radiation was scattered over a large area and made its way into the sea, air and food chain in the weeks and months after the disaster.

Tens of thousands of people were evacuated from their homes around the plant and swathes of the area remain badly polluted. The clean-up is proceeding slowly, amid warnings that some towns could be uninhabitable for three decades.

Last month TEPCO began the process of asking for a one-trillion-yen injection of public cash because of the company's "very serious financial condition", president Toshio Nishizawa told a news conference at the time.

The firm separately asked for an additional 846 billion yen in financial aid to pay ballooning compensation bills.

Nishizawa said at the time that he wanted to keep TEPCO as a private entity.

Edano, however, stood firm behind the idea that TEPCO had to come largely under government control and told the company to come up with an overhaul plan if it wanted the money.

If the fresh cash injections are approved, the total amount of taxpayers' money handed to TEPCO would add up to 3.5 trillion yen.