Tokyo: The head of the Tokyo Electric Power Co. (TEPCO)- the company operating Japan's troubled Fukushima Daiichi nuclear power plant is stepping down, media reports said on Friday.

Katsutoshi Chikudate, a senior executive of TEPCO will replace Masataka Shimizu as the company head, a news portal reported quoting Japan's newspaper.

After stepping down, Shimizu will taking responsibility for the handling of Japan's nuclear crisis.

The Fukushima Daiichi nuclear power plant was heavily ravaged by a powerful earthquake and a subsequent tsunami in mid-March, which resulted in massive radiation leak. About 80,000 people have been evacuated from a 12-mile zone around the plant, where radiation levels soared following the quake.

Post leaks, TEPCO has come under harsh criticism, including from Japan's Prime Minister Naoto Kan, for insufficient efforts to tackle the nuclear crisis, the worst since the 1986 Chernobyl disaster.

Shimizu was also criticised for staying in Tokyo for weeks before visiting the Fukushima prefecture in mid-April, the website said. In March, he was reported to have been suffering dizziness and high blood pressure 'through overwork' for a few days.

TEPCO has pledged to bring the crippled Fukushima Daiichi reactors to a stable state by January. The company's loss is expected to reach a historic maximum of $15 billion in the fiscal year ending in March due to recovery efforts, the largest deficit since the company opened in 1951, a website said, quoting a source close to TEPCO.