The announcement comes after months of investigations into allegations of corruption in the planning and sponsorship of Olympic and Paralympic events.
Tokyo-based Dentsu is known as Japan’s largest advertising agency.
The Japan Fair Trade Commission (FTC) said it has filed complaints against advertising agencies Hakuhodo DY Holdings, Tokyo Agency, Fuji Creative Corporation, Cerespo and Same Two.
“We have determined that this is a malicious and serious case that will have a wide impact on people’s lives,” said Goh Okumura, an investigator at the FTC.
Dentsu, Cerespo and Fuji Creative were banned for nine months from bidding on contracts with Japan’s ministries of industry, foreign affairs and education.
Last year, Haruyuki Takahashi, a former member of the Tokyo 2020 Olympics organizing committee and former executive at Dentsu, was arrested on suspicion of taking bribes from Olympic sponsors.
Takahashi was accused of receiving a $380,000 payment from workwear retailer Aoki Holdings, the official partner of the Tokyo 2020 games.
Takahashi denied the allegations.