Japan PM apologises for LDP's church ties

Revelations of long-running links between some MPs of the ruling Liberal Democratic Party and the church have become a headache for Kishida, denting his approval ratings, and have fanned opposition against a state funeral planned for slain former premier Shinzo Abe.

Abe's suspected assassin bore a grudge against the church, officially called the Family Federation for World Peace and Unification, alleging it bankrupted his mother, and blamed Abe for promoting it, according to his social media posts and news reports.

The church, founded in South Korea in the 1950s and known for its mass weddings, has over the years faced questions over how it solicits donations.

The government has said Abe's funeral, to be held on September 27 at Tokyo's Nippon Budokan hall, would cost about 250 million yen ($A2.6 million), excluding outlays for security and the reception of overseas dignitaries.