The boss of Fukushima operator TEPCO on Friday met local leaders to ask for their blessing to restart the world's biggest nuclear plant after a public tongue-lashing for bypassing them this week.

Tokyo Electric Power Co said Tuesday they would ask Japan's nuclear watchdog for the green light to re-fire two of the seven units at Kashiwazaki-Kariwa in northern Niigata prefecture.

The entire power station has been shuttered since around 12 months after the tsunami-sparked meltdowns at Fukushima in March 2011.

While the Nuclear Regulation Authority (NRA) determines if a plant meets safety requirements, the decision to allow reactors to come back online rests with politicians.

On Friday TEPCO president Naomi Hirose received a dressing down for not having first consulted the plant's host community.

"We are very disappointed that you announced you will ask the Nuclear Regulation Agency for permission (to restart nuclear reactors) without any explanation to us," Kashiwazaki mayor Hiroshi Aida told Hirose.

"Such a move can ruin the mutual trust we have been building," the mayor said.

In a meeting that was carried on national television news programmes, Hirose was seen bowing deeply and offering his contrition.

"We sincerely apologise for your having had cause to criticise us for making hasty and sloppy decisions without giving considerations to local opinions," Hirose said.

Hirose also met the mayor of Kariwa, the other municipality where part of the power station is located, and will meet Niigata's governor later in the day.

TEPCO and local governments have signed a deal under which the utility must get local leaders' permission before re-opening the plant.

Although the agreement is not legally binding, TEPCO has admitted it will be difficult to restart reactors if local people are opposed. Public wariness of the once-trusted technology has made nuclear power a politically toxic issue.

All but two of Japan's 50 atomic reactors are offline, shut down for safety checks after the Fukushima disaster, the worst the world has seen since Chernobyl.

Following criticism that the nuclear industry was in bed with its regulators in the lead-up to Fukushima, the government established a new industry watchdog, whose beefed up safety standards come into force on Monday.

The NRA's chairman on Thursday said the new rules would give Japan one of the best nuclear safety regimes in the world, although he acknowledged it would take time for the safety culture to grow.

Reactors at Fukushima went into meltdown when their cooling systems were swamped by the huge tsunami of March 2011.

Tens of thousands of people were forced from their homes by the threat of radiation, with some still unable to return.

Although the nuclear accident is not officially recorded as having directly killed anyone, the natural disaster claimed more than 18,000 lives and was one of Japan's worst ever peacetime tragedies.