Civic groups have staged a protest against the upcoming state funeral of Japan's former prime minister, as Prime Minister Kishida Fumio has sought understanding for his decision at an out-of-session Diet meeting.

Abe Shinzo was shot to death while making an election campaign speech in July. His funeral is scheduled for September 27 in Tokyo. The cost is expected to total nearly 12 million dollars.

The organizers said 500 people participated in the protest held in front of the prime minister's office on Thursday.

One of the participants, journalist Kamata Satoshi, said Kishida's decision to hold the funeral without parliamentary approval violates the Constitution.

He added that forcing people to express their condolences is tantamount to the state abusing the freedom of thought.

A 29-year-old woman said it is questionable to hold the funeral using a huge amount of taxpayers' money, as many people are struggling amid the coronavirus pandemic.

The government claims that the Cabinet Office Establishment Act says the office has control over matters regarding state ceremonies, and the Cabinet decision has a legal basis for the funeral.

The government also says it will not call on citizens to mourn the former prime minister.