Prime Minister Shigeru Ishiba vowed to go all out for this summer's House of Councilors election at an annual convention of his Liberal Democratic Party in Tokyo on Sunday.

"I will devote myself and make my utmost efforts to win (the upcoming Upper House election) without fail," Ishiba, also president of the LDP, said in a speech where he asked fellow party members to "unite and act for the nation, the people and the next era."

The triennial Upper House election comes after the LDP-Komeito ruling coalition lost its majority in the House of Representatives, the lower chamber of the parliament, in last year's general election.

Following the LDP's high-profile political funds scandal, Ishiba said: "We should be humble before sovereign voices. We will restore the attitude that we had when we were out of power."

Regarding the government's decision to cancel a plan to raise the ceiling on out-of-pocket medical expenses in August, the prime minister said, "The only way to regain trust is to listen to the voices of people in weak positions and facing hardships."

The LDP convention had guests including Komeito head Tetsuo Saito, Masakazu Tokura, chairman of the Japan Business Federation, or Keidanren, and Tomoko Yoshino, president of the Japanese Trade Union Confederation, or Rengo.

It is the first time in 20 years that Rengo's president has attended the LDP's convention.

Before the LDP marks the 70th anniversary of its founding on Nov. 15 this year, LDP Secretary-General Hiroshi Moriyama announced a plan to map out a new vision for the nation in the coming years.

Also at the convention, the party adopted its 2025 activity program, which calls for drawing up a political reform plan to restore trust damaged by the funds scandal.