Japan's Prime Minister Yoshihiko Noda toured the crippled Fukushima power station Sunday in a show of resolve over the nuclear disaster there, amid strong public scepticism about his energy policy.

Noda, who reshuffled his cabinet last week before a possible snap general election, encouraged the crews who worked to contain the plant's dangerous molten reactors after last year's earthquake and tsunami, TV footage showed.

"I believe that Japan has survived as we see it now thanks to your dedicated work," the premier told about a dozen people who carried on working inside the power station after the catastrophe struck on March 11, 2011.

"As a Japanese, I want to thank you for exerting yourself in a frightening and demanding environment," he said at an accommodation facility for workers just outside the 20-kilometre (12.5 mile) no-go zone surrounding the plant.

The quake and tsunami knocked out the Fukushima Daiichi power station's cooling systems, sparking the world's worst nuclear accident since the 1986 Chernobyl disaster.

The plant, 220 kilometres northeast of Tokyo, has continued releasing radiation into the environment, forcing tens of thousands of residents to evacuate the region.

"I believe that your work in various places on the frontline has enabled us to embark on efforts to decommission the reactors," said the premier, clad in workman's clothing.

After changing into white protective gear, Noda travelled to the power station and inspected a reactor where workers were planning to remove spent nuclear fuel from a storage pool.

It was Noda's second visit to the plant -- he went there immediately after taking office in September last year.

"Without Fukushima's revival, Japan's revival will never happen. I want you to make further efforts toward the decommissioning of the reactors," he told some 200 workers.

He also observed operations to decontaminate an elementary school inside the evacuation zone.

"Decontamination is the key to Fukushima's restoration and revival. We need to accelerate the speed of decontamination," Noda told reporters at the end of the day trip.

His government declared last month it was aiming to eliminate nuclear power from the country's energy mix by 2040.

But his trade minister said immediately afterwards that two partially-built reactors could be finished and put to work, leading doubts to be cast on the government's intentions.