Chubu Electric Power Co. President Akihisa Mizuno said Monday that the company agreed to a request last week by Japanese Prime Minister Naoto Kan to suspend the Hamaoka nuclear power plant in Shizuoka Prefecture for safety concern.

"We decided at today's final extraordinary board meeting to suspend operation of the No. 4 and 5 reactors and postpone restarting of the No. 3 reactor," Mizuno told a news conference.

The utility, Japan's third biggest, decided that the firm will mothball reactors No. 1 and No. 2 and idle the No. 4 and No. 5 reactors at Hamaoka plant, which serves central Japan, following the prime minister's direct request coupled with a government report indicating an 87 percent likelihood of a magnitude-8 earthquake or higher striking the area within 30 years.

Naoto Kan asked Chubu Electric Co. to stop operation in Hamaoka on Friday, quoting safety concerns that the nuclear power plant lacks medium- to long-term measures for protection against disasters, such as embankments.

Naoto Kan welcomed the decision, saying the government will make utmost efforts to avoid power shortage in the central region of the Honshu island, an economic power house of Japan.

Japanese government reached the conclusion to suspend Hamaoka plant after evaluating the country's 54 reactors for quake and tsunami vulnerability after the magnitude 9.0 earthquake and ensuing tsunami on March 11 devastated the Pacific coastal regions of northeastern Honshu.

Japan's Minister of Economy, Trade and Industry Banri Kaieda said the country's other nuclear plants will not be suspended and the ministry is ready to financially support Chubu Electric Power Co. over Hamaoka.

The company continued operating the 1,137-megawatt No. 4 reactor and the 1,380-megawatt No. 5 reactor at Hamaoka plant after the March 11 disaster, which crippled Tokyo Electric Power Co.'s Fukushima No 1. nuclear plant and led to Japan's worst nuclear crisis.

The 1,100-megawatt No. 3 unit at Hamaoka has been shut for regular checks since November 2010, while No. 1 and No. 2 reactors are in the process of being scrapped.

The plant sits 190 kilometers southwest of Tokyo on a dangerously active fault-line that seismologists monitor carefully for increasing seismic activity.

Concerns about electricity shortages in summer when demand peaks following a shutdown of Hamaoka will purportedly be offset by increased output by non-nuclear power generation.

The Hamaoka plant in Shizuoka, populated by 3.75 million people, is known as "the most dangerous" nuclear power plant in Japan due to its aged reactors, proximity to a massive fault-line and coastal area and inability to sustain a sizable earthquake similar to the quake and tsunami that crippled Fukushima No.1 plant on March 11.