An extraordinary session of parliament, originally scheduled for this week and expected to elect a new prime minister, will now convene on Oct 21, the Japanese government notified the Diet on Wednesday. But the exact timing of the vote has yet to be decided.

Sanae Takaichi, the newly elected leader of the Liberal Democratic Party, said on Tuesday that she "will never give up" although some people doubt she will become prime minister despite her election as party president.

According to Kyodo News, a series of meetings between ruling and opposition party leaders, as well as within opposition parties, is scheduled for later Wednesday possibly until night.

The LDP is also set to hold separate talks at the Diet in the afternoon with the Constitutional Democratic Party of Japan and the Democratic Party for the People, and Takaichi is expected to meet with Japan Innovation Party leader Hirofumi Yoshimura later the same day.

On Tuesday, the secretary-generals of the ruling LDP and the opposition DPFP held meetings. The LDP is seeking the DPFP's cooperation in managing Diet affairs, with an eye to forming a coalition.

Meanwhile, the largest opposition force, the CDP, is working to unite opposition parties in a bid to make DPFP leader Yuichiro Tamaki the next prime minister, Japanese media reported.

After Sanae Takaichi won the ruling LDP's presidential election on Oct 4, its junior coalition partner Komeito said last week it would quit the coalition government, citing an "insufficient" response to a political funding scandal, and would not back her in the upcoming Diet vote.

The LDP currently holds 196 of the 465 seats in the House of Representatives, while Komeito holds 24. The LDP holds 100 of the 248 seats in the House of Councillors, while Komeito holds 21.

The election of a new prime minister, initially expected this week, has been postponed amid ongoing political uncertainty. Voting will take place in both the upper and lower houses, with the lower house's decision prevailing in the event of a tie. If no candidate secures a majority in the first round in either chamber, a runoff will be held between the top two contenders.