Eight million people signed an Internet petition demanding an end to nuclear power and hundreds of thousands joined public protests. Yet Japan handed an election landslide to the most pro-atomic option on offer.

Anti-nuclear activists have been left licking their wounds after the first national poll since the tsunami-sparked disaster at Fukushima saw an apparent melting away of public anger as the country welcomed back the establishment.

"A problem was that political divisions emerged over when and how to stop nuclear power," said Hideyuki Ban, co-director of the Citizens' Nuclear Information Center, an anti-nuclear advocacy group.

"It would have been ideal if the parties had came together under a simple, broad goal of ending nuclear power. But parties had to differentiate themselves from others for the election. Maybe it was inevitable," he said.

The Liberal Democratic Party bagged 294 of the 480 seats in the lower house, crushing their opponents, the biggest of which won only 57 seats.

Where smaller parties offered an end to nuclear power -- immediately, over ten years, or within three decades -- the LDP pledged only to "decide" on reactor restarts within three years.

Commentators say the pro-business party is likely to give the green light to power companies. Markets agree, with shares in Fukushima operator Tokyo Electric Power (TECPO) surging around 50 percent in two days after the win.

The problem, said the left-leaning Asahi Shimbun newspaper, was that other issues trumped nuclear; voters were frustrated with Japan's economic malaise, huge public debts, fragile employment and diplomatic friction with China.

The public were looking for a way to punish the ruling Democratic Party of Japan for its policy failures.

But as the DPJ teetered on the electoral edge, a barrage of new political parties sprang up.

Analysts say this crowded electoral field confused voters, who in the end opted for familiar names and faces, as represented by the LDP.

Even in nuclear-scarred Fukushima prefecture, the party won four out of five districts.

In fact, says the Asahi, the anti-nuclear vote was almost completely neutralised because of the fragmentation caused by this mushrooming of parties.

Some 78 percent of people who voted said they wanted nuclear power to end now or to be phased out, the Asahi said.

Many of their votes were divided among four parties other than the LDP, according to the Asahi, which added that the LDP also received votes from people who wanted an end to nuclear.

"All major parties, except for the LDP, pledged to end nuclear power with varying degrees of policy emphasis. As a result, the anti-nuclear votes were divided," the newspaper said.

Activists say the speed with which the election rapidly appeared to be a fait accompli caused them problems.

"Voters were bombarded by a series of opinion polls calling the LDP the winner long before the election," said Greenpeace campaigner Kazue Suzuki, adding that a record low voter turnout of 59.32 percent did not help their cause.

Japanese politics specialist Koichi Nakano of Sophia University said single issue candidates would always find it difficult to get to parliament.

The political culture tends to favour candidates from established parties with organised supporters, while independents face a tough time, he said.

Ban from the Citizen's Nuclear Information Center said activists have not given up hope and think their movement will gather lost momentum once the new government moves to restart reactors, idled since the Fukushima crisis.

"The public has become well aware about nuclear energy, renewable energy and energy saving, and how they are interconnected," he said. "There is no turning back."