TOKYO: Japanese police have questioned a former head of the nuclear safety body regarding possible criminal charges over the Fukushima nuclear crisis, news reports said Sunday.

Prosecutors have interviewed Haruki Madarame, former chief of the Nuclear Safety Commission who was responsible for giving the government technical advice about the crisis, national broadcaster NHK quoted sources as saying.

It said Madarame appeared voluntarily for questioning and was apparently asked to explain how he dealt with the disaster triggered by the March 2011 tsunami.

Fukushima residents have filed a criminal complaint with prosecutors against Madarame on suspicion of professional negligence which resulted in deaths and injuries, the public broadcaster said.

The complaint alleges that Madarame was responsible for a delay in announcing data predicting how radiation would spread from the crippled Fukushima nuclear power plant, it said.

It also reportedly faults him for failing to take necessary measures to shield the plant against the tsunami in the first place.

When he resigned in September, Madarame hinted that his commission had failed in its responsibility to avert the nuclear disaster, saying: "We have to sincerely reflect on it. We apologise to people."

Madarame, who became the body's chief in 2010, accompanied then prime minister Naoto Kan as they monitored the plant from a helicopter days after the tsunami struck the plant.

NHK said prosecutors have separately questioned executives of plant operator Tokyo Electric Power Co including former chairman Tsunehisa Katsumata, but it was uncertain if individuals could be charged over the disaster.

The Yomiuri Shimbun said prosecutors were likely to decide on whether to charge Madarame and others as early as March.

The huge tsunami, which was triggered by a 9.0-magnitude earthquake, crashed into the Fukushima power station and swamped cooling systems, sparking meltdowns.

The reactors were out of control for months, spewing radiation over a wide area and forcing the evacuation of hundreds of thousands of people.

Japanese experts said they brought the wrecked units under control in December 2011. But melted fuel remains inside their cores and their full decommissioning and cleaning-up is expected to take decades.

In July last year a parliamentary report said Fukushima was a man-made disaster caused by Japan's culture of "reflexive obedience" and not just by the tsunami that hit the plant.

TEPCO has admitted it had played down known tsunami risks for fear of the political, financial and reputational cost. It says no one has died as a direct result of radiation.