Japan's ruling coalition will likely win more than half of the seats being contested in Sunday's House of Councillors 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 and Komeito, the Japan Innovation Party and the Democratic Party for the People as well as some independents -- are also in sight of maintaining the two-thirds majority required to initiate proposals for constitutional reform, the telephone survey conducted from Saturday to Tuesday showed.

People listen to a politician making a stump speech in Kawasaki in Kanagawa Prefecture, eastern Japan, on July 5, 2022, for the House of Councillors election on July 10. (Kyodo) ==Kyodo

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.

The Kyodo News poll shows the LDP and Komeito are tipped to grab more than 63 of the 124 seats, with the ruling party alone projected to gain over 60. Komeito is expected to retain 14.

Among major opposition parties, the Constitutional Democratic Party of Japan is facing a tough battle to hold on to the 23 seats it currently holds and the Japan Innovation Party may see a big increase from six, the survey showed.

The Japanese Communist Party is looking at six seats in the election, while the Democratic Party for the People could lose half of its seats.

Prime Minister Fumio Kishida, who heads the LDP, has set a goal for the ruling parties of maintaining a majority in the upper house, which is seen as a relatively low target given that they only need to win 55 seats this time to cross that threshold.

The election is crucial for Kishida, who took office last October, to ensure political stability amid COVID-19 and the crisis in Ukraine.

The projected result of the election could still change as 39.6 percent of the respondents in the survey, which received replies from 43,766 eligible voters, were undecided on who to vote for in electoral districts, with the corresponding figure for proportional representation at 38.1 percent.

Voters will cast two ballots -- one to choose electoral district representatives and one under proportional representation.

Accelerating inflation, defense and energy policy are among the key issues during campaigning as Russia's war against Ukraine continues.

The major political parties agree on the need for steps to cope with rising prices that are directly hitting households at a time of tepid wage growth.

But the LDP differs from opposition parties like the CDPJ on the issues of boosting national defense spending and revising the pacifist Constitution for the first time since its promulgation in 1946.

Any proposed revision would need to be approved by two-thirds majorities in both the upper and lower houses before it can be put to a national referendum. Pro-amendment forces held a two-thirds majority in the upper chamber before the election and they currently do so in the more powerful House of Representatives or lower house.

One focus of the election is on 32 single-seat electorates. The latest survey shows the LDP leading in a majority of the districts.