TOKYO (Reuters) -Japan's Fair Trade Commission said on Tuesday it filed criminal complaints against Dentsu and five other firms as well as seven individuals over alleged bid-rigging on contracts for the Tokyo 2020 Olympics.

The complaint marks the latest development in months of investigations into alleged corruption in the planning and sponsorship of the Tokyo Olympics and Paralympics Games, held in 2021 after a pandemic-driven postponement.

"We determined that this is a malicious and serious case that will have a broad impact on people's lives," FTC investigator Goh Okumura told a media briefing.

The other companies named in the complaint are Hakuhodo DY Holdings Inc, Tokyu Agency Inc, Fuji Creative Corporation, Cerespo Co and Same Two Inc, the FTC said.

All six companies had no immediate comment when contacted by Reuters. Tokyo prosecutors are planning to the bring the charges on Tuesday, Kyodo News agency said.

Prosecutors this month arrested a former Tokyo Olympics organising committee official and executives at Dentsu and others over the case, in which the agencies were suspected of colluding in 2018 to rig the bids for the Games' test events.

Dentsu, Cerespo and Fuji Creative have already been barred from bidding for contracts at the industry, foreign and education ministries for nine months.

The bid-rigging case comes after a bribery scandal, in which Haruyuki Takahashi, a former member of the Tokyo 2020 Olympics board and before that a Dentsu executive, was arrested last year on suspicion of receiving bribes from Olympic sponsors.

Executives from advertising firm ADK Holdings, business suits retailer Aoki Holdings and publishing firm Kadokawa have also been arrested in connection with the bribery case.

(Reporting by Satoshi Sugiyama, Kantaro Komiya, Kaori Kaneko; Editing by Chang-Ran Kim and Edwina Gibbs)