Japan's government believes radiation-contaminated water has been leaking into the Pacific Ocean from the wrecked Fukushima Daiichi nuclear plant for the past two years, an industry ministry official told reporters on Wednesday.
Earlier, the official said an estimated 300 tonnes of contaminated water was leaking into the ocean per day from the Fukushima nuclear plant.
Also on Wednesday, Prime Minister Shinzo Abe pledged to step up government efforts to stem the leaking of radioactive water.
Abe ordered the Minister of Economy, Trade and Industry to urgently deal with the situation and ensure the plant's operator, Tokyo Electric Power Co, takes appropriate action to deal with the cleanup, which is expected to take more than 40 years and cost $11 billion.
The plant was severely damaged in an earthquake and tsunami in March 2011.