Official campaigning on Friday began for nationwide elections to pick assembly members in 41 prefectures and 17 major cities across Japan.

The races are part of the quadrennial local elections that were unified to cut costs and improve voting rates. This year, voters will go to the polls on April 12, the same day gubernatorial elections will be held in 10 prefectures. Another round will be held on April 26.

Both the ruling and opposition parties are trying to shore up their bases to prepare for the critical House of Councilors election next year.

The outcome of the polls will be closely watched because the ruling Liberal Democratic Party has failed to win strong support in recent gubernatorial elections, despite its convincing victory in the snap House of Representatives election last December, which set a new record for low turnout.

Prime Minister Shinzo Abe has placed priority on regional economic revitalization, saying his team will make sure any benefits from "Abenomics," his trickle down economic program, will be shared across the country. But he is also trying to gain support for security legislation as he moves to rewrite the Constitution.

Around 3,263 people filed candidacies for 2,284 assembly seats in the 41 prefectures, according to a Kyodo News tally. In this round, however, prefectural assembly elections will not be held in Iwate, Miyagi, Fukushima, Ibaraki, Tokyo and Okinawa.

In 17 of the nation's 20 government-designated cities, 1,475 people had filed to run for 1,022 city assembly seats, according to the tally.

The LDP, which won 1,119 prefectural assembly seats in 2011, has increased its candidates by around 70 to over 1,300. Komeito, its junior partner in the ruling coalition, is fielding about 170.