Japan's election campaign kicked off Tuesday with party leaders making pitches near the disaster-struck Fukushima plant, setting the tone for a poll set to be dominated by nuclear power and the sluggish economy.

Around 1,500 candidates, fielded by 12 parties or standing as independents, are vying for the 480 seats in the lower house of parliament in the December 16 election.

Opinion polls have suggested the main opposition Liberal Democratic Party (LDP) is on course to come back to government as the biggest party, giving the country its seventh prime minister in six years.

But no single grouping looks likely to secure a majority.

Observers say the election could lead to a feeble coalition government at a time the resource-poor, ageing nation needs to make key decisions on its energy policy and on measures to boost the economy and tackle its massive public debt.

Japan is also embroiled in territorial rows with South Korea and China and must decide whether to join talks on forming a trans-Pacific free trade group, a move highly unpopular with its protected farmers.

Party leaders seem to have begun campaigns in the capital but at least four were in Fukushima prefecture Tuesday to highlight their reconstruction credentials.

Prime Minister Yoshihiko Noda, head of the Democratic Party of Japan (DPJ), pitched for voter support in Iwaki, just south of the nuclear power plant crippled by the March 2011 earthquake and tsunami.

"We will make a start for Japan's revival by affirming anew that there will be no revival of Japan without revival of Fukushima," Noda said.

"The point in question is whether we will move ahead with tasks we must tackle or will go back to old politics," he said, accusing the LDP of turning the clock back on social security and nuclear policies.

LDP leader Shinzo Abe was in Fukushima city, 50 kilometres (30 miles) away from Fukushima Daiichi, the scene of the world's worst atomic accident in a quarter of a century.

Abe, who is advocating spending where Noda pushes for fiscal restraint and tax hikes to rein in public debts, said he would aim for a society that will enjoy growing income.

He said the LDP and its ally, the Buddhists-backed Komei, would win power as anti-nuclear activists showed up holding signs proclaiming "It's the LDP that built the nuclear plant in Fukushima".

The DPJ pledges to phase out nuclear power by the 2030s while the business-friendly LDP says only that it will decide over the coming three years whether to restart reactors that were taken offline after the disaster.

The centre-left DPJ swept to power in 2009, bringing an end to an almost half-century of unbroken rule by the conservative LDP.

The upcoming vote will be a verdict on the their three-year rule, which included the turbulent months after the nuclear disaster plunged the nation into its biggest crisis since World War II.

Newly formed parties are attracting voters who are fed up with the DPJ and LDP.

The strongest among the new "third force" parties is the Japan Restoration Party, launched this year by the maverick mayor of Osaka, Toru Hashimoto, and now headed by outspoken former Tokyo governor Shintaro Ishihara.

The Hash-Ish union, as some have dubbed it, pledged to strengthen surveillance in Japan's seas in the wake of a bitter row with China over the sovereignty of a disputed archipelago.

Another force is the Tomorrow Party of Japan, set up last month by Yukiko Kada, an expert on environmental studies and governor of the western prefecture of Shiga. She has vowed to get rid of nuclear power in 10 years.

The party has taken in veteran power broker Ichiro Ozawa and his supporters who stormed out of the DPJ in protest at a sales tax hike.