TOKYO -- The coalition led by Japan's ruling Liberal Democratic Party (LDP) is certain to lose its majority in the House of Councillors following Sunday's election, public broadcaster NHK reported.

NHK said that the coalition of the LDP and Komeito is set to fall short of the 125 seats needed for a majority in the 248-seat upper house of parliament.

The House of Councillors is made up of 248 members with fixed six-year terms. Elections are held every three years, with half the seats up for election each time. In Sunday's vote, a total of 125 seats, including one to fill a vacancy, were up for grabs.

Meanwhile, the main opposition Constitutional Democratic Party of Japan is expected to expand its seat count, while the Democratic Party for the People and Sanseito look set to make significant gains, NHK projected.

Despite the defeat, Shigeru Ishiba has expressed his intention to stay on as Japan's prime minister, adding that the LDP must fulfill its responsibility as the ruling party.

Ishiba told NHK that his party has so far secured enough seats to be the leading party in the upper house, and that he has to fulfill the pledges he made during the election campaign, such as wage hikes to counter rising prices.

The embattled prime minister is expected to hold a press conference on Monday, while all major opposition parties have expressed reluctance to help the ruling bloc by forming an expanded coalition.

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.