TOKYO (Reuters) - Prime Minister Shinzo Abe's ruling coalition is expected to secure a big victory in Sunday's upper house election, surveys showed on Wednesday, resolving six years of parliamentary stalemate and further weakening the opposition.
Support for Abe's Liberal Democratic Party has consistently far outstripped that for other parties in the run up to the election, buoyed by hopes that his push for hyper-easy monetary policy, public spending and structural reforms would reinvigorate Japan's economy.
Half of the upper house's 242 seats come up for election every three years.
Voter preference polls taken between Sunday and Tuesday published by the Kyodo News agency, the Nikkei and Yomiuri dailies showed the LDP and its coalition partner, the New Komeito, were likely to win more than 70 of the 121 seats up for grabs.
That would secure a majority in the upper house for Abe's bloc. It would also end the "twisted parliament", in which the opposition controls the upper house, giving it the ability to hamper policy implementation.
However, even with control of both houses of parliament, there are doubts about the extent of Abe's commitment to potentially painful reforms that critics say are needed to revive the economy's growth over the longer term.
The surveys showed the main opposition Democratic Party of Japan could suffer its worst electoral defeat in its 15-year history, dealing another blow to the party that was kicked out of power in December's lower house elections.
The DPJ held 44 seats up for grabs this time but was likely to come away with fewer than half that number, the Nikkei poll said. Other opposition parties like free market proponents Your Party could gain some seven seats, while the conservative Japan Restoration Party could get around six, Kyodo's poll shows.
Still, the Nikkei poll found about a fifth of voters are undecided. Voter turn-out is expected to be low.
Japan has suffered parliamentary gridlock ever since Abe led the LDP to a massive defeat in a 2007 upper house vote. He quit abruptly two months later.
The DPJ faced a similar headache after sweeping to power in 2009, only to lose a 2010 upper house election.
The hawkish Abe, 58, returned to power for a rare second term after the December lower house election.
(Reporting by Antoni Slodkowski; Editing by Neil Fullick)