Dick Pound, a senior member of the International Olympic Committee, said a games held with grandstands full of only Japan residents would run counter to the Olympics' cosmopolitan spirit.
Speaking to Kyodo News in a telephone interview on Monday, Pound said local organizers are exploring a simplified Olympics and that a move beyond 2021 is still seen as unrealistic.
Shutting out international spectators due to worries about travel during the coronavirus pandemic is also not yet on the cards.