A group of 50 people, including civic group members, asked a Tokyo court on Thursday to issue an injunction ordering a stop to a state funeral for slain former Prime Minister Shinzo Abe.

The request to the Tokyo District Court, coming on the eve of a Cabinet decision to hold the rare funeral likely on Sept. 27, seeks to halt use of the national budget if the Cabinet goes ahead with the plan.

It would only be the second state funeral for a former prime minister in postwar Japan, and the opposition camp has expressed concerns that the funeral, to be fully funded by the government, could be used to cement the legacy of the divisive figure.

"There are voices within society and the opposition parties that are against holding a state funeral," Masamichi Tanaka, head of the civic group's secretariat, said during a press conference in Tokyo. "It should be discussed in parliament."

The civic group, which aims to monitor abuse of power by authorities, also plans to file a lawsuit against the use of taxpayer money for the planned funeral.

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.