Image caption Mr Noda is trying to convince the public that nuclear power is vital

Japan must restart two nuclear reactors to protect the country's economy and livelihoods, Prime Minister Yoshihiko Noda has said in a televised broadcast.

Measures to ensure the safety of two reactors at western Japan's Ohi nuclear plant have been undertaken, he said.

Since last year's Fukushima nuclear disaster, Japan's 50 reactors have been shut down for routine maintenance.

The crisis fuelled immense public opposition to nuclear power, but Japan is facing a summer of power shortages.

Japan's last nuclear shut down for routine maintenance was in May. When the third reactor at the Tomari plant in Hokkaido prefecture was switched off, Japan was left without energy from atomic power for the first time in more than 40 years.

Public confidence in nuclear safety was shaken by the meltdowns at the Fukushima power plant, triggered by last year's devastating earthquake and tsunami.

Analysis In making the television address, Prime Minister Yoshihiko Noda has very publicly taken responsibility for restarting the nuclear reactors. Indeed, it was a condition set by the governor of Fukui, which hosts the Ohi plant, before he gives his blessing. The government had hoped to build more of a national consensus. Ministers have spent weeks wooing local leaders. But nuclear power is a hugely controversial issue in Japan. Mr Noda warned Japanese society cannot survive without cheap and stable power. He could now make a formal decision to restart the two reactors at Ohi. They are the first to have gone through new stress tests to check their resistance to natural disasters. But any decision by Mr Noda could unleash strong criticism. Opinion polls show many Japanese would rather try to get through the summer by cutting back on their electricity consumption.

"Cheap and stable electricity is vital. If all the reactors that previously provided 30% of Japan's electricity supply are halted, or kept idle, Japanese society cannot survive," Mr Noda said.

He added that some companies could possibly move production out of Japan, losing vital jobs as a result.

"It is my decision that Ohi reactors No 3 and No 4 should be restarted to protect the people's livelihoods," he said.

Controversial move

Mr Noda and members of his cabinet could make a formal decision by next week if the governor of Fukui prefecture, where the reactors are located, agrees.

But the move is extremely controversial, reports the BBC's Roland Buerk.

Earlier this week, a third of governing party members of parliament petitioned Mr Noda, urging him to exercise "greater caution" over the issue.

Protests met the prime minister's announcement in central Tokyo, with people waving placards stating, "We oppose restarts".

His statement was made only a few hours after the former president of the Fukushima plant operator testified before a high-profile investigative panel appointed by parliament.

Masataka Shimizu said that he did not consider a pullout of the plant's workers during the height of the crisis as had been alleged.

In April, the government set stricter safety guidelines for nuclear plants in a bid to win public confidence for restarts. These include the installation of filtered vents and a device to prevent hydrogen explosions.

Last month, the government asked businesses and households in parts of the country to cut electricity usage by up to 15% to avoid possible blackouts.