Scrambling hard to tackle its worst atomic crisis, Japan said on Wednesday it will scrap four stricken reactors at the quake-hit Fukushima nuclear facility, as radiation seeping into seawater reached its highest level yet and the President of the troubled plant's operator hospitalised.

Tokyo Electric Power Company (TEPCO), the plant's operator, said that it will decommission the four reactors at the plant, more than two weeks after the monster magnitude-9 quake and tsunami struck Japan's northeast leaving nearly 30,000 people dead or unaccounted for.

"We have no choice but to scrap reactors 1 to 4 if we look at their conditions objectively," Tsunehisa Katsumata, the company's Chairman, said at a press conference.

His remarks came hours after the company announced that its President, Masataka Shimizu, was hospitalised on Tuesday for hypertension and dizziness, the latest crisis to hit the embattled TEPCO which is struggling hard to contain the atomic crisis.

His hospitalisation follows reports that 66-year-old Shimizu had fallen sick on March 16 and taken some days off from manning a liaison office set up between the government and the utility to regain control of the plant.

Katsumata has already taken over Shimizu's role temporarily in leading efforts to bring the crisis under control, the company said, adding that the President would return to work as soon as he recovers.

TEPCO said that while the cost of compensation in connection with the nuclear disaster will be daunting and undermine it financially, the company will try hard to remain afloat and avoid nationalisation, Kyodo reported.

After losing their cooling functions due to the deadly natural disaster on March 11, four of the six reactors at the nuclear power plant, 220 km northeast of Tokyo, have leaked radioactive materials into the air and sea.

As workers continued their efforts to prevent the reactors from overheating and restore their cooling systems, Katsumata apologised for the crisis at the plant.

"We apologise for causing the public anxiety, worry and trouble due to the explosions at reactor buildings and the release of radioactive materials," he said.

He said the company would make maximum efforts to restore the cooling systems of the Nos. 1-4 reactors to bring them into a stable condition called "cold shutdown". The Nos.5 and 6 reactors were already in a state of cold shutdown.

"Our greatest responsibility is to put everything into bringing the current situation to an end and under control," Katsumata said.