Tokyo: Japanese voters headed to the polls Sunday to cast their ballot in a parliamentary election with Prime Minister Shinzo Abe’s ruling party expected to cruise to victory despite lukewarm support.

Abe, in power since late 2012, has yet to achieve a strong recovery in the world’s third-largest economy nor his cherished goal of removing a war-renouncing clause from Japan’s US-imposed constitution.

But voters, despite misgivings, appear willing to boost his party and its conservative allies, due mostly to a lack of faith in the opposition.

Sunday’s vote is for half the seats in the House of Councillors — the less powerful upper house of parliament — and polling stations across the country opened at 7:00am (2200 GMT Saturday).

The vote outcome is expected to become clear shortly after the polls close at 8:00pm.

Having been largely written off after a failed 2006-2007 stint as prime minister, Abe got a rare second chance when a left-leaning government collapsed in late 2012.

He promised to end debilitating deflation through massive easy money and other steps — so-called Abenomics — while beefing up Japan’s defence, promoting conservative values and vowing to revise the constitution.

Initial results were favourable with stocks soaring and businesses reaping record profits as the yen fell, making Japanese companies more competitive.

But the world’s third-largest economy has since lurched from growth to contraction, with weak consumer inflation still weighing on sentiment.

In a poll last week, 41 per cent said they disapproved of Abe’s economic policies, but support his Liberal Democratic Party (LDP), a less-than-resounding 37 per cent, far outpaced 11 per cent for the main opposition Democratic Party.

‘As in past elections, voters are likely to passively endorse the Abe administration due to a lack of alternatives,’ said Koji Nakakita, professor of politics at Hitotsubashi University in Tokyo.

A wildcard this time is that Japan’s voting age has been lowered from 20 to 18 to encourage young people to take part in politics but how they will vote, and in what numbers, remains to be seen.

Abe is hoping that the coalition and a loose group of hawkish conservatives from smaller parties can grab a two-thirds majority in the upper house, giving him the strength to start amending the constitution.

The document, which renounces Japan’s right to wage war, is deplored by nationalists as a relic from Japan’s World War II defeat.

Still, many Japanese staunchly embrace its pacifist ideal.

But any legislation that mustered the two-thirds majorities needed to pass both houses would face another hurdle in the form of a national referendum.