Japan's nuclear watchdog Wednesday gave a green light to plans to restart two reactors, more than three years after the Fukushima disaster.

However, hurdles still remain, including getting the consent of local communities in a country still scarred by the catastrophe where all 48 viable reactors are offline.

The go-ahead from the Nuclear Regulatory Authority (NRA) comes after it issued a more than 400-page safety report in July, saying two reactors at the Sendai plant in southern Japan were up to scratch, and follows a month-long public consultation period.

After having considered around 17,000 public comments that it received, the regulator confirmed it believed the two units met required standards and gave its written approval.

But any restart is unlikely before the year end as the operator, Kyushu Electric Power, is also required to get more NRA approvals for other remedial work at the site.

More challenging, perhaps, is gaining the consent of communities living near the plant in southwestern Kagoshima prefecture, who must sign off on the restarts before they can happen.

More than three years after the disaster at Fukushima, where a tsunami sent reactors into meltdown, the Japanese public remains unconvinced of the safety of the technology.

Much of the job of convincing a sceptical nation will fall on the shoulders of new industry minister Yuko Obuchi, a 40-year-old mother-of-two with an impeccable political pedigree.

"If people say they are worried, I think it is only natural. If you are a mother, I think it is a kind of feeling that everyone has," she had said soon after being appointed as the nation's first female industry minister.

"The central government must offer a full explanation to these sentiments."

She has highlighted the importance of earning the "understanding of hosting communities", who may be hostile to the prospect of firing up nearby reactors, despite beefed up safety rules.

The minister has reportedly dispatched five central government officials to help local bodies in Kagoshima draw up evacuation plans in case of an accident.

- Lessons of Fukushima -

Communities living right next door to nuclear plants, who often enjoy grants from utility companies and depend on the power stations for employment, are frequently sympathetic to restarts.

However, there is often hostility from those living further afield who enjoy no direct benefits but see themselves as in the firing line in the event of another accident like Fukushima.

Greenpeace Japan, which is campaigning for Tokyo to abandon nuclear power completely, said the government of Prime Minister Shinzo Abe appeared to be glossing over the last year, in which Japan has survived without nuclear power.

"The government... is ignoring the lessons of Fukushima and attempting to prevent the renewable energy revolution, trying to take the nation back to its dependence on dangerous and unreliable nuclear power," said the organisation's Kazue Suzuki.

"The government should be focusing its efforts on managing the ongoing nuclear disaster at Fukushima, supporting its victims, and abandon its plans to restart nuclear reactors."

Abe has been trying to persuade a wary public that the world's third largest economy must return to an energy source that once supplied more than a quarter of its power.

Widespread anti-nuclear sentiment has simmered in Japan ever since an earthquake and tsunami in March 2011 caused meltdowns at the Fukushima power plant, sparking the worst atomic disaster since Chernobyl.

Tens of thousands of people were evacuated from their homes, many of whom have not been allowed to return, with scientists warning some areas might have to be abandoned forever.

Following the catastrophe, the country's nuclear reactors were switched off. Two reactors were briefly restarted last year but all of Japan's nuclear plants are currently offline.

Obuchi visited Fukushima Daiichi nuclear plant on Sunday, donning a protective Tyvek jacket and a heavy face mask to observe work at the crippled facility.