Most Japanese voters would support higher taxes to help massive rebuilding after last month's earthquake and tsunami, newspaper opinion polls showed on Monday, and they want a new prime minister to lead the effort.

Japan is also struggling to bring the Fukushima Daiichi nuclear plant under control after it was damaged by the March 11 natural disasters and began leaking radiation, a process that could take the rest of the year.

Plant operator Tokyo Electric Power Co. (TEPCO) said on Sunday it hoped to achieve a cold shutdown to make the reactors stable within six to nine months.

Full recovery could take even longer, the government has said, while rebuilding the shattered northeastern coast has yet to begin.

The cost of material damages alone from the quake and tsunami has been estimated at $300 billion, making it the world's most costly natural disaster. More than 13,000 people have been confirmed dead, and tens of thousands made homeless.

Nearly 70 per cent of people surveyed by the Nikkei business daily said Prime Minister Naoto Kan should be replaced, and a similar number said the government's response to the nuclear crisis was not acceptable.

"Japan has experienced many crises in the past, but I believe this is the biggest crisis in the 65 years since the end of World War Two," Kan, who has been has heavily criticized for what many see as failure to lead, told a parliamentary panel on Monday.

"From now on ... we must persist with our strategy on two fronts, and I want to make every effort on both issues (recovery and the nuclear crisis)."

The government hopes to avoid issuing new bonds to fund an initial emergency budget, expected to be worth about 4 trillion yen ($48 billion), due to be compiled this month.

But bond issuance is likely for subsequent extra budgets and markets are worried that post-quake rebuilding may hamper Japan's efforts to rein in its debt, which already stands at twice the size of its $5 trillion economy.

"It is no doubt that a substantial amount of revenue sources will be needed for reconstruction," Japan's deputy finance minister Fumihiko Igarashi said on Monday.

"I want to ask the people to share burdens broadly. While we review every spending and revenue to raise funds, everyone needs to share the pain."

LACK OF LEADERSHIP

Kan's Democratic Party of Japan (DPJ) was punished in local elections last weekend, losing nearly 70 seats.

More than half of the people surveyed by the Nikkei newspaper want the DPJ to team up with the main opposition Liberal Democratic Party (LDP), and another poll in the Mainichi newspaper showed a similar result.

Kan has already invited the LDP to form a national unity government, but the LDP has rejected the idea of a coalition and called for Kan to resign. The DPJ controls parliament's lower house but needs opposition help to pass bills because it lacks a majority in the upper chamber, which can block legislation.

Analysts say that Kan, who took office last June as Japan's fifth leader since 2006, is unlikely to resign readily, while opposition parties could be criticized if they try to take disaster budgets hostage in a political battle.

Support for Kan's government stood at 27 percent, up five points from February, in the Nikkei poll.

Most voters said Kan has not shown leadership in response to the crisis. In the Mainichi survey, 58 percent said they do not trust government information on the atomic accident.

Japan's economics minister warned last week that the damage was likely to be worse than first thought as power shortages would cut factory output and disrupt supply chains.

Japan's nuclear disaster has also raised concern in the United States about President Barack Obama's push for expanded nuclear energy to help wean Americans off their dependence on foreign oil.

Hillary Clinton, the chief U.S. diplomat, visited Japan on Sunday, urging the country to remain active on the world stage and pledging support for a key ally in East Asia. Washington has deployed thousands of troops plus military aircraft and navy ships to help with relief work.