Widely circulated reports say the government wants to allow up to 10,000 people at some sports and cultural events.
Hashimoto said if Tokyo decides to allow fans, the rules will have to be much stricter than for half-filled stadiums in Japan for baseball or soccer.
There is this risk of people who come to the games, and after watching they stop by bars and restaurants before going home.
Japan has attributed just over 14,000 deaths to COVID-19 and has controlled the virus better than many countries, but not as well as many in Asia.