TOKYO, July 6 (Reuters) - Prime Minister Shinzo Abe's ruling bloc is headed for a big victory in this month's upper house election, media surveys show, a win that would end a parliamentary deadlock and set the stage for Japan's first stable government since 2006.
The anticipated victory would give the Japanese leader a mandate for his "Abenomics" recipe that aims to end prolonged stagnation with a mix of hyper-easy monetary policy, fiscal spending and structural reforms including deregulation.
However, a big win could also be a mixed blessing if members of his Liberal Democratic Party (LDP), buoyed by victory and with no national election required until 2016, oppose painful reforms many say are needed to revive growth.
Newspaper surveys taken on July 4-5 and published on Saturday showed the LDP and its coalition partner, the New Komeito party, were on track to win more than 70 of the 121 seats up for grabs in the July 21 poll for the 242-seat chamber.
With the coalition's 59 uncontested seats, that would hand them a hefty majority and end a "twisted parliament" in which the opposition controls the upper house, hampering policy implementation.
"Hubris is a big problem," said Chuo University political science professor Steven Reed. "The real question is whether the LDP has really become more unified or whether it was just a way of getting back in power."
Japan has had seven prime ministers since the LDP's charismatic Junichiro Koizumi ended a rare five-year term in 2006. Abe succeeded Koizumi, only to quit abruptly after leading the LDP to a massive upper house loss in 2007.
The hawkish Abe, 58, returned to power in December for a rare second term after the LDP-led bloc handsomely won a December election for parliament's powerful lower house. The coalition, however, has since lacked a majority in the upper chamber, which can block legislation.
The LDP could even win the 72 seats it needs to secure an upper house majority on its own, the Asahi newspaper forecast showed, the first time the long-dominant conservative party has done so since losing there in 1989. The LDP would still be unlikely to dump New Komeito because it relies on the lay Buddhist group that backs the smaller party to help get votes.