Tokyo 2020 president Seiko Hashimoto is "100%" certain the Olympics will go ahead, but warned the Games "must be prepared" to proceed without spectators in the event of a coronavirus outbreak.
There are 50 days until the delayed Tokyo Games begin on 23 July.
Japan is dealing with a fourth wave of coronavirus cases, with 10 areas of the country under a state of emergency, reports the BBC.
Hashimoto told BBC Sport: "I believe that the possibility of these Games going on is 100% that we will do this."
"The question right now is how are we going to have an even more safe and secure Games.The Japanese people are feeling very insecure and at the same time probably feel some frustration at us talking about the Olympics and I think that is giving rise to more voices opposing having the Games in Tokyo," Seiko Hashimoto added.
"The biggest challenge will be how we can control and manage the flow of people. If an outbreak should happen during the Games times that amounts to a crisis or an emergency situation then I believe we must be prepared to have these Games without any spectators.
"We are trying to create as complete a bubble situation as possible so we can create a safe and secure space for people who come in from overseas as well as people who are in Japan, the residents and citizens of Japan."