TOKYO (Reuters) - Prime Minister Shinzo Abe's ruling bloc looks set for a handsome upper house election win on Sunday, cementing his grip on power and setting the stage for Japan's first stable government since the charismatic Junichiro Koizumi left office in 2006.
The victory would give the hawkish leader a stronger mandate for his recipe to revive the economy and spell his personal political redemption after he led his Liberal Democratic Party (LDP) to a humiliating defeat in a 2007 upper house election.
The ensuing parliamentary deadlock allowed the opposition to block legislation and led to Abe's resignation two months later. That "twisted parliament" has hampered policies for most of the six years since and led to a string of revolving-door leaders.
"I want to see a stable government. That's the Liberal Democratic Party," said 76-year-old Hiroshi Miyamoto, after casting his ballot for Abe's pro-business, conservative party in the western Tokyo suburb of Hachioji.
Abe, 58, who returned to power after a big win in December's lower house poll for his LDP and coalition partner New Komeito, has said he will remain focused on fixing the economy with his "Abenomics" mix of hyper-easy monetary policy, fiscal spending and structural reforms.
But some worry that Abe's resolve for economic reform could weaken in the face of a resurgent LDP. A landslide victory could bolster opposition to regulatory reform from LDP lawmakers with close ties to industries that would suffer from change.
Critics also worry Abe will shift his focus to the conservative agenda that has long been close to his heart, and concentrate on revising the post-war pacifist constitution and recasting Tokyo's wartime history with a less apologetic tone.
Such a shift, along with moves to strengthen Japan's defense posture, would further fray ties with China and South Korea, where bitter memories of Japan's past militarism run deep. Tokyo is already engaged in tense territorial rows with Beijing and Seoul over tiny, uninhabited islands.
"I have the impression that Prime Minister Abe wants to revise the constitution, though I don't think it will be easy," said apparel firm employee Etsuko Yamada, 35, who voted for the opposition Japanese Communist Party.
"I want him to show Japan's presence through diplomacy with strong negotiating power, not though military power by spending money to rearm."
Abe has declined to say he whether as premier he will visit Tokyo's Yasukuni Shrine for war dead, where Japanese leaders convicted by an Allied tribunal as war criminals are also honoured. A visit on the August 15 anniversary of Japan's defeat in World War Two would spark outrage in the region.
A Reuters poll showed Japanese firms generally want the LDP to win the election but worry that a landslide victory will allow Abe to prioritise nationalist policies over the economy, as critics say he did during his troubled 2006-2007 term.
Voting began at 7 a.m. (2200 GMT) and closes at 8 p.m. (1100 GMT), when media will project the outcome based on exit polls. Final results will be known late on Sunday or early on Monday.
Media forecasts show the LDP and New Komeito are on track to win more than 70 of the 121 seats up for grabs in Sunday's poll for the 242-seat upper house.
With the coalition's uncontested 59 seats, that would hand it a hefty majority, solidifying Abe's grip on power and raising the chances of a long-term Japanese leader for the first time since the reformist Koizumi's rare five-year term ended in 2006.
Forecasts also show the LDP has a shot at winning an upper house majority in its own right for the first time since 1989, although analysts and politicians say it is unlikely to dump its coalition partner, on which it relies to help get votes.
But the LDP and two smaller parties that back Abe's drive to revise Japan's pacifist constitution to legitimise the military looked likely to fall short of the two-thirds majority needed to take revisions of the charter to a public referendum. Those parties already have two-thirds of the lower house seats.
Media also forecast that the main opposition Democratic Party of Japan, which surged to power in 2009 to end more than half a century of almost non-stop LDP rule only to be ousted last year, could suffer its biggest drubbing since its founding in 1998. That would raise concerns about prospects for a competitive two-party democracy.
"I don't want the LDP to derail and do whatever it wants, just because it is popular," said Hideo Houri, a 61-year old civil servant who voted for the Democrats. (Additional reporting by Chikafumi Hodo, Kaori Kaneko, Yuka Obayashi, Yoshiyuki Osada, Kiyoshi Takenaka and Osamu Tsukimori; Editing by Clarence Fernandez)