TOKYO -- Japan's ruling coalition of the Liberal Democratic Party (LDP) and Komeito is unlikely to keep its majority in the House of Councillors following Sunday's election, media reports said.

Voting for the upper house election, where half the seats are up for grabs, ended at 8 pm local time. The ruling camp is at risk of losing its majority, public broadcaster NHK projected, citing its exit poll.

Prime Minister Shigeru Ishiba's LDP and its small ruling partner Komeito must win at least 50 of the 125 contested seats to clear the majority line. They are forecast to secure 32 to 51 seats, according to NHK.

For the opposition, NHK projected that the largest Constitutional Democratic Party could expand its seats, while the Democratic Party for the People and Sanseito look set to make significant gains.

A Kyodo News exit poll also showed that the ruling bloc is struggling to retain its majority in the 248-seat upper house of the Diet in the election.

Currently, the LDP and Komeito have 75 seats that are not up for re-election. Failure to secure 50 seats in this election would plunge Japan into political turmoil, as Ishiba would have to seek support from opposition parties in the upper house, Kyodo News said.

LDP Secretary-General Hiroshi Moriyama avoided giving concrete comments on TV, saying that "vote counts are still ongoing and I would like to refrain from commenting on the nature of responsibility at this time."

In the October 2024 general election, the ruling coalition already lost its majority in the more powerful House of Representatives, or lower house, forcing Ishiba to form Japan's first minority government in over three decades.