Masataka Shimizu, the president of the power company, also said he is working with the government to create a plan to provide short-term compensation to the many affected by the nuclear crisis.

“I regret the fact we are inconveniencing all these people, I want to take this opportunity to apologize,” Shimizu said.

His speech comes after Japan's prime minister vowed to wind down the month-long crisis at the Fukushima Daiichi power plant "at all costs”.

Prime Minister Naoto Kan said he wants Tokyo Electric Power Company, to produce a timetable for bringing the disaster to an end, “and they will be doing that soon”.

Shimizu did not provide a detailed timetable during his speech on April 13 but said his company is working to stop harmful materials from going into the atmosphere "as soon as possible”.

Japan declared the Fukushima Daiichi crisis a Level 7 event on the international system for rating nuclear accidents on April 11, putting it on par with the 1986 Chernobyl disaster in the former Soviet Union. The top-scale designation was based on the massive release of radioactivity since the accident began, particularly in its early days, and classifies Fukushima Daiichi a "major accident" requiring long-term countermeasures.

Scientists believe the amount of radiation released is only a tenth of what was released at Chernobyl, said Hidehiko Nishiyama, the chief spokesman for Japan's Nuclear and Industrial Safety Agency. But the levels for radioactive iodine and cesium that have been spewed into the air, water and soil around the plant are in the thousands of trillions of bequerels - 15 times higher than the threshold for a top-scale event.