Hundreds of people affected by the Fukushima nuclear crisis in Japan filed a class action lawsuit Monday demanding greater efforts to clean up the contaminated region two years on from the disaster.

Some 800 plaintiffs filed the case with the Fukushima District Court, demanding 50,000 yen ($520) a month each from the government and Tokyo Electric Power Co (TEPCO) until the area is restored, their lawyers said in a statement.

The plaintiffs are mostly from Fukushima, but also include some residents of neighbouring prefectures, the lawyers said.

"Through this case, we seek restitution of the region to the condition before radioactive materials contaminated the area, and demand compensation for psychological pains until the restitution is finished," the statement said.

The case was filed as Japan marked the second anniversary of a 9.0-magnitude earthquake on March 11, 2011, which unleashed a giant tsunami along the northeastern Pacific coast.

The natural disasters killed nearly 19,000 people, including those whose bodies are yet to be recovered.

The huge waves crippled reactors at the Fukushima Daiichi nuclear plant, which went through meltdowns and explosions, spewing radioactive materials into surrounding areas.

The Fukushima accident forced tens of thousands of residents near the area to abandon their homes and jobs in heavily contaminated areas. It is not clear when they can return home, if ever.

"Through this case, we will clarify the responsibility of TEPCO, which caused the accident, and the government which neglected to take sufficient safety measures and promoted nuclear power with utilities as a national policy," the statement said.

"This case is not only aimed at saving victims, but also at pushing the government to thoroughly change its pro-nuclear policy and therefore prevent people becoming victims in the future," it said.

The court filing came as people all over Japan bowed their heads in silence to remember those killed by the tsunami two years earlier.

Ceremonies were held in towns and cities throughout the disaster zone, as well as in Tokyo, where Emperor Akihito and Empress Michiko led tributes to those who lost their lives in the natural disaster.

No one is officially recorded as having died as a direct result of the disaster at Fukushima.