Tokyo: Magnifying the nuclear crisis due to the quake-affected nuclear power plant, a total of 250 tonnes of highly contaminated radioactive water have leaked into the sea in May from the No.3 reactor at the Fukushima nuclear power plant, the plant's operator has said.

The nuclear power plant was badly damaged in the March 11 earthquake and following tsunami.

The Tokyo Electric Power Co. (TEPCO) said on Saturday that the water contained an estimated 20 terabecquerels of radioactive substances.

The leak is estimated to have lasted for 41 hours from 2 a.m. May 10 through 7 p.m. the following day.