Japanese Prime Minister Shinzo Abe's coalition cruised to a big election win on Sunday, ensuring he will stick to reflationary economic policies and a muscular security stance, but record low turnout pointed to broad dissatisfaction with his performance.

NHK public TV said Abe's Liberal Democratic Party and junior partner the Komeito party were assured more than the 317 seats in the 475-member lower house required to maintain a two-thirds "super-majority" that smoothes parliamentary business.

But the LDP was set to fall slightly short of the 295 it held before the poll, NHK figures showed.

"I believe the public approved of two years of our 'Abenomics' policies," Abe said in a televised interview. "But that doesn't mean we can be complacent."

Many voters, doubtful of both the premier's "Abenomics" strategy to end deflation and generate growth and the opposition's ability to do any better, stayed at home.

Rare 2nd term

Final turnout will be a record low of 52.4 per cent, media forecast, below 59.3 per cent in a 2012 poll that returned Abe to power for a rare second term on pledges to reboot an economy plagued by deflation and an aging, shrinking population.

Market analysts said the widely expected outcome would be positive for shares and negative for the yen in the near term given expectations Abe will stick to a "Three Arrows" strategy of hyper-easy monetary policy, government spending and reforms.

"Since the Abe administration puts emphasis on share prices, short-term, this will be a tailwind for higher stocks and a weaker yen," said Tsuyoshi Ueno, senior economist at NLI Research Institute.

"But medium-term, investors will be watching to see if Japan is changed structurally."

Doubts persist over whether Abe will knuckle down on his "Third Arrow" of reforms in politically sensitive areas such as labour market deregulation and an overhaul of the highly protected farm sector.

Progress has been limited so far, partly due to opposition from members of Abe's own party.

'Abenomics' hits hurdles

Hopes for Abenomics were hit when Japan slipped into recession in the third quarter following an April sales tax rise. Wage increases have not kept pace with price rises and data suggest any economic rebound is fragile.

Abe decided last month to put off a second tax hike to 10 percent until April 2017, raising concerns about how Japan will curb its huge public debt, the worst among advanced nations.

"Between now and the delayed tax increase, we need to revive the economy and find a path to fiscal rebuilding," said LDP legislator Shinjiro Koizumi. "If you think about it in that way, even though we have won, there is no room here for celebrating."

Abe, whose support has now sagged well below 50 percent, called the election after just two years in office to strengthen his grip on power before tackling unpopular policies.

They include restarting nuclear reactors taken off-line after the 2011 Fukushima disaster and a security policy shift away from post-war pacifism.

The LDP-led coalition victory could ease Abe's path to re-election in a party leadership race next September, boosting the likelihood, but by no means guaranteeing, that he stays in power through 2018 and becomes one of Japan's rare long-term leaders.

The main opposition Democratic Party of Japan (DPJ) was set to fall short of the 80 seats some predicted they would win, largely due to voters' memories of a 2009-2012 rule plagued by policy flip-flops, infighting and three premiers in three years.

Return to one-party dominance

DPJ leader Banri Kaieda, criticized by many in his own camp for lack of charisma, lost his seat, NHK reported. The party's limp performance has raised concerns Japan is returning to one-party dominance that characterized politics for decades.

The Japan Communist Party was on track to more than double its eight seats, winning support from protest voters loath to back the Democrats.

Abe could turn his attention from the economy to a conservative agenda that includes laying the groundwork for revising the post-war, pacifist constitution and recasting Japan's wartime past with a less apologetic tone.

That agenda raises hackles in China and South Korea, where bitter memories of Japan's past militarism run deep.

"Revising the constitution has been our party's long-time aspiration ... But the hurdles for achieving this are very high," Abe said on Sunday. "We need to continue efforts to deepen the public's understanding (of the need to do this)."

Despite hefty wins, the LDP stumbled on the southern island of Okinawa, host to the bulk of the U.S. military in Japan, boding ill for a plan to relocate a controversial U.S. Marines air base that many residents want off the island altogether.

LDP candidates lost in all four districts on the island, media said.