TOKYO (Kyodo) -- Japanese Prime Minister Shigeru Ishiba on Monday dismissed the idea of expanding the ruling coalition's composition for now but expressed a desire to incorporate policy ideas from the opposition camp after a crushing defeat in the previous day's general election.

His remarks came as expectations mounted that his Liberal Democratic Party may seek policy-by-policy deals with the Democratic Party for the People, which saw its seats in the 465-member House of Representatives more than quadruple from seven on Sunday, to prevent political gridlock.

The two parties have already been contacting each other "at the secretary general level," the DPP's leader Yuichiro Tamaki told a TV program on Monday.

On Monday, Ishiba described the election outcome, in which the ruling bloc lost its majority in powerful lower house, as "harsh," vowing to fundamentally reform the party to restore voter confidence shaken by a slush fund scandal.

While the LDP's goal of retaining its majority along with its coalition partner, the Komeito party, was not achieved, Ishiba said he will continue as prime minister to lead the government and tackle growing economic and security challenges.

"We cannot afford political gridlock," Ishiba said at a press conference at LDP headquarters, adding, "We'll adopt what should be adopted" from the policies of opposition parties that have gained momentum, while fostering a cooperative relationship with them.

The main reason behind the election defeat is that "we failed to address people's suspicion, distrust and anger over the underreporting of political funds and the issue of money in politics," Ishiba said.

The ruling coalition's seats dropped sharply to 215 from 288, marking the first time in 15 years they have lost majority control. Seats won by the main opposition Constitutional Democratic Party of Japan surged to 148 from 98.

According to a Kyodo News exit poll, 74 percent of voters considered the slush fund scandal when casting their ballots. Even among LDP supporters, 68 percent did so, suggesting the scandal influenced their voting behavior.

The LDP has come under intense scrutiny amid revelations that some of its factions, particularly its largest, which was led by former Prime Minister Shinzo Abe before his 2022 assassination, neglected to report portions of their income from fundraising parties and created slush funds for years.

Earlier in the day, Ishiba, elected LDP president late last month, called for intraparty unity in the wake of the major setback in the general election that could make it difficult for him to remain as leader of the government.

The LDP's election strategy chief, Shinjiro Koizumi, resigned to take responsibility, while incumbent Cabinet members, including Justice Minister Hideki Makihara, lost their seats. Makihara has voiced his intention to step down on Sunday.

The LDP has begun talks on how to sustain Ishiba's government ahead of a special parliamentary session to be held within 30 days following the lower house election to elect the next premier. Opposition parties have ruled out joining the current coalition.

The government and ruling camp are arranging to call the special Diet session on Nov. 11, sources close to the matter said.

Ishiba, who only took office on Oct. 1, had considered Nov. 7, but his government has revised the plan to allow more time to try and form a majority for the prime ministerial vote, the sources added.

In another development, the leaders of the two opposition parties, which are traditionally supported by Rengo, the Japanese Trade Union Confederation, met with Tomoko Yoshino, head of the country's largest labor union, a day after the general election.

The DPP's Tamaki assured Yoshino that his party will not join the LDP-Komeito coalition. His party and the CDPJ are both offshoots of the now-defunct Democratic Party of Japan.

After the talks, however, Tamaki told reporters that his party is open to policy coordination discussions with other parties, such as the LDP and the CDPJ, adding that he plans to vote for himself in the session rather than for Noda.

The CDPJ, meanwhile, is exploring ways to join hands with other forces, aiming to bring about a change of government, with leader Yoshihiko Noda saying he will hold "sincere" discussions with other opposition parties in the run-up to the special Diet session.

Noda, who served as prime minister for over a year until December 2012, when the DPJ was ousted from power by the LDP in a general election, became the leader of the CDPJ in September.