The opposition Japanese Communist Party on Thursday launched a probe into lawmakers' ties to the Unification Church after the assassination of former Prime Minister Shinzo Abe shed light on such ties, including those involving ruling Liberal Democratic Party members.

At the first meeting of the JCP's investigative team, Akira Koike, head of the party's Secretariat, said cases of "collusion" between lawmakers, including those from the LDP, and the religious group have been brought to light.

Akira Koike, head of the Japanese Communist Party's Secretariat, speaks at the first meeting of a team established to investigate the connections between the political world and the Unification Church, held in parliament on July 21, 2022. (Kyodo)

Alleging that politics played a role in the Unification Church changing its name to the Family Federation for World Peace and Unification in 2015 in Japan, Koike said the team will look into whether there was collusion or administrative problems in the episode.

At the same meeting, a journalist who had covered the group's activities when he was a reporter for the JCP newspaper Shimbun Akahata presented his opinions.

The team, which primarily aims to scrutinize the church's activities and its connection to the political world, will also hear from the National Network of Lawyers Against Spiritual Sales and other organizations.

Separately, Chinami Nishimura, secretary general of the main opposition Constitutional Democratic Party of Japan, said Thursday her party will launch a task force on Monday to investigate damage caused by the religious group.

Nishimura said her party's consumer affairs committee will hear from the same lawyers' group on Friday.

"This is an issue that the Diet cannot overlook. We will investigate, verify, and formulate measures," Nishimura told reporters.

Abe was fatally shot on July 8 while delivering a stump speech on a street in the western city of Nara. The assailant, Tetsuya Yamagami, said he harbored a grudge against the church for more than 20 years and killed Abe as he believed his grandfather had invited the group to Japan from South Korea, according to investigators.

Yamagami's uncle has said the man's mother donated about 100 million yen ($724,000) in total to the Unification Church.