Voters in Japan went to the polls Sunday in an election likely to return conservatives to power at a time of growing tension with China and as the nation seeks to arrest economic decline.

Media surveys show the Liberal Democratic Party on course for a convincing victory in the lower-house election, with the Democratic Party of Japan led by Prime Minister Yoshihiko Noda set to be ousted in the race for the premiership.

Some opinion polls even show the conservative LDP, with its coalition partner, achieving the two-thirds majority in the 480-seat chamber needed to override decisions by the upper house, in which no single party has a majority.

Polls opened early Sunday and exit polls from broadcasters will be released shortly after the ballot boxes are sealed at 8:00 pm (1100 GMT).

Voter turnout was 27.40 percent as of 2 pm, down by 7.79 points from the previous 2009 poll, the government said.

Hawkish LDP president Shinzo Abe appeared set for a return to office, after a campaign in which he has sketched out a harder line on foreign policy, as tensions rise with China over disputed islands in the East China Sea.

Abe, whose brief stint as premier in 2006-7 ended ignominiously, has pledged to right Japan's listless economy, which has suffered years of deflation, made worse by a soaring currency that has squeezed exporters.

"With stronger monetary policies, fiscal policies and growth policies, we will end deflation, correct a high yen and grow the economy," said Abe Saturday.

"It's time to put an end to the confusion and doldrums of three years and three months," Abe said, referring to the stint in power of Noda's Democratic Party of Japan (DPJ).

"We've got to take a fresh step forward. Please join us for the fight," added the former premier, whose party ruled Japan almost continuously for more than five decades until it was ousted by the DPJ.

He has also pledged to raise spending on infrastructure projects at a time when large parts of the tsunami-ravaged northeast have yet to see significant rebuilding following the March 2011 catastrophe.

The collapse of an ageing highway tunnel that claimed nine lives earlier this month lent credence to his calls, which have been criticised by opponents as a return to the LDP's "construction state" of the last century.

Public unease about a worsening security environment -- North Korea launched a rocket over Japan's southern islands last week and China sent a plane into Japanese airspace -- has bolstered Abe's cause.

He has promised to strengthen defences and revitalise a security alliance with the United States that is widely thought to have drifted under Noda's party.

"It is an urgent task to rebuild the Japan-US alliance as unshakable and achieve peace and stability in Asia," Abe's LDP said in a statement before the Sunday vote.

The DPJ disappointed voters who handed it a hefty majority in 2009 polls. Policy missteps, diplomatic gaffes and vicious factional infighting saw it burn through three premiers in as many years and squander its electoral hand.

A plodding and sometimes confused response to the disaster at Fukushima, where nuclear reactors went into meltdown after the tsunami last year, did it no favours either.

Opinion polls show that despite a strong anti-nuclear feeling in Japan, an array of smaller parties promising an atomic exit may struggle to get much traction.

"Let us have another try... a lot of promises have yet to be fulfilled," Noda was quoted as saying in newspaper adverts published on Sunday.

But Etsuko Suzuki, a 33-year-old businesswoman, had no hesitation in showing her disappointment at Noda's DPJ, saying at a polling station: "The DPJ just let me down. They could not do anything in the end."

Other voters say there is little enthusiasm for any party. Commentators note that the LDP's likely victory will come from their perceived status as the least worst option.

"I don't expect much from politics," Toyoki Endo, 73, said at the polling station. "I came here to vote, but I did not have any particular parties in mind. I want politicians to show results with action, not just words."