Japan's government on Tuesday released an energy policy document in which nuclear power is considered an important electricity source.

The plan is a toned-down revision of a draft document released in December, which said nuclear power also serves as a "foundation" for the stability of the country's energy supply, Kyodo News Service reports.

The government is required to review its energy plan at least every three years. The last plan, in 2010, called for Japan to boost its reliance on nuclear power to about 50 percent of its total electricity in 2030.

Prior to the Fukushima nuclear power plant crisis, triggered by a massive earthquake and tsunami in March 2011, nuclear power provided nearly 30 percent of Japan's electricity.

The plan released Tuesday does not include any numerical targets for Japan's medium- to long-term energy mix.

"It was impossible to plan any energy mix, as it's been unclear how many reactors can come back online," Industry Minister Toshimitsu Motegi told reporters, the Wall Street Journal reports.

While all of Japan's 48 operable nuclear reactors remain offline since the Fukushima disaster, 17 are now undergoing screening for possible restarts by the Nuclear Regulation Authority under stricter regulations introduced after Fukushima.

The Journal cited a survey conducted over the weekend by major broadcaster Fuji Television which found that 53 percent of 1,000 respondents said they oppose the restart of any of the country's idled reactors.

The energy plan states that "nuclear power is an important baseload electricity source," which means that nuclear plants would remain at the core of power production along with coal-fired and hydroelectric power plants.

The plan is expected to be approved by Prime Minister Shinzo Abe's Cabinet by the end of March, the Financial Times reports.

Abe, who came into office in late 2012, has called for restarting Japan's idled nuclear plants as a source of low-cost power for economic growth.

Former Prime Minister Naoto Kan, who led the country's response to the Fukushima disaster and subsequently aimed to phase out nuclear power by the end of the 2030s, criticized the importance given to nuclear power in the energy plan.

"This government has not learned the lessons of Fukushima," Kan was quoted as saying by the New York Times Tuesday. "Japan was on the brink. But now, we want to go back to nuclear for economic reasons. But what happens to the economy if another disaster hits?"

Earlier this month, two anti-nuclear candidates, including former Prime Minister Morihiro Hosokawa, were defeated in Tokyo's gubernatorial election, giving the central government a boost of confidence to move forward with nuclear power.