Giant piles of debris from Japan's earthquake and tsunami scar the country's once picturesque northeast coast -- and the clear-up is hamstrung by fears the rubbish may be contaminated by radiation.

Decades-worth of waste was left behind when the waters receded in March last year after claiming more than 19,000 lives.

The survivors are desperate to rebuild, but must first get rid of more than 22 million tonnes of rubbish -- far too much for the disaster-struck region to deal with alone.

But despite appeals to national solidarity, worries over nuclear contamination from the crippled Fukushima power plant mean virtually no one elsewhere in Japan wants the debris processed near them.

"We hope everything will be taken away as quickly as possible so we can go back to normal life," said one man from the devastated town of Onagawa.

According to Environment Minister Goshi Hosono facilities across the entire country will have to be brought into play to deal with the 16 million tonnes of debris from Miyagi prefecture and 4.42 million tonnes from Iwate -- amounts that dwarf the annual average waste generated by both areas.

Hosono, who is also responsible for handling the atomic crisis, agrees the 2.28 million tonnes of waste in Fukushima will have to be treated on site as radioactive elements have been released into the environment in the prefecture.

When the disaster struck a national outpouring of empathy brought with it offers of help from all over the country.

But these have since dried up and now there are few volunteers for taking waste from Miyagi and Iwate, amid fears it could be contaminated and would be dangerous to burn despite the use of filters in incinerators.

"We want to finish (the clean-up) in three years, but if things continue at the current rate that seems difficult, so we must accelerate," said Hosono.

"We are taking additional measures, such as constructing temporary incineration sites, but even that will not be enough" without other municipalities playing a part, he said.

The city of Tokyo has already agreed to take some of the debris, "but other localities have not decided anything," he complained.

The government has sought to reassure opponents with a dedicated website aiming to explain exactly how the waste is dealt with.

It says the incinerators have fine enough filters to prevent radiation being released, and only waste below specific radiation levels will be burned in conventional facilities.

Hosono says ash produced by the incineration is safe.

"The radioactivity measured in the ash is 133 becquerels per kilogramme, which is lower than the temporary level set for food, so there is no danger and no need to worry," he said.

According to his ministry, radiation limits have been set for clear-up workers at one millisievert per year, the same as that allowed for the general public under normal circumstances. Incineration plants are not allowed to expose local residents to more than 0.01 millisieverts per year.

The Tokyo authority's own website also details the precautions being taken there, and explains how many times radiation is measured to ensure that nothing dangerous makes it to the capital from Miyagi and Iwate.

Even so that has not been enough to assuage the fears of some people living in the megacity.

"We received some 4,000 letters of complaint (about this)," Masami Imai, director of the city's waste department, told AFP.

"In more than 85 percent of them, citizens say they are worried about radioactivity or even say that we should refuse to import this debris.

"They worry about their children, they are afraid that radiation levels are too high."

Radiation experts agree that children are at greatest risk from cancers and genetic defects because they are still growing, are more prone to thyroid cancers, and because they will have more time to develop health defects.

But Yoshiaki Suda, mayor of Onagawa, appealed for sympathy.

"We want to rebuild at all costs," he said. "To do that we have to clear the rubble as soon as possible.

"I wish people in Tokyo and other areas would understand the situation we are in."