Japan's ruling coalition will likely win more than half of the seats being contested in Sunday's Upper House election, according to a Kyodo News poll showing it has a solid lead over opposition parties.

Pro-constitutional amendment forces — the ruling coalition of the Liberal Democratic Party (LDP) and Komeito, as well as Nippon Ishin no Kai and the Democratic Party for the People and some independents — are also in sight of maintaining the two-thirds majority required to initiate proposals for constitutional revision, the telephone survey conducted from Saturday to Tuesday showed.

Upper House members serve six years in Japan. A total of 125 seats will be up for grabs in the election — half of the 248 seats in the chamber and one to fill a vacancy in the other half.