Japan's new industry minister Yuko Obuchi said Sunday the resource-poor nation should be realistic about its energy needs as the government tries to convince a sceptical public on the necessity of nuclear power.

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.

The difficult task of winning them round has fallen to Obuchi, appointed the country's first female minister of economy, trade and industry by Prime Minister Shinzo Abe.

"It would be very difficult to make the decision not to have nuclear power right now," Obuchi said during a live debate programme on public broadcaster NHK.

"It's an issue difficult to explain in short phrases -- we have to take seriously voices of concerns after the accident in Fukushima," she said, following her visit to the disaster-stricken plant two weeks ago.

However, with Japan's energy self-sufficiency rate at just six percent, compared with the United States' 85 percent and France's 50 percent, energy costs were soaring, she said.

"After the Fukushima accident, the cost of fossil fuel imports jumped by 3.6 trillion yen ($33 billion), or 10 billion yen ($92 million) per day."

In pre-Fukushima Japan, nuclear power accounted for nearly one-third of the country's energy needs.

The minister stressed that an independent nuclear watchdog set up in the aftermath of the disaster had "the world's strictest safety guidelines".

As a result, "The government policy is to restart a nuclear plant that has passed these guidelines," she said.

An unsteady supply of renewable energy from solar and wind power and the need to reduce CO2 emissions meant Japan could not afford to rely heavily on fossil fuels, she added.

Japan's nuclear watchdog earlier this month 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.

Widespread anti-nuclear sentiment has simmered in Japan ever since the earthquake and tsunami in March 2011 caused meltdowns at Fukushima, 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.