The Tokyo Olympics could take place with no spectators in attendance if the Japanese capital is placed into another state of emergency, the nation's prime minister Yoshihide Suga has said.

Japan is moving ahead with plans to host the Games, which were postponed by a year due to the coronavirus pandemic, despite strong public opposition and warnings from health officials that crowds could lead to increased infection rates.

International fans are already banned from attending, with a decision on domestic spectators due to be taken on Monday.

On Sunday, the state of emergency that had been imposed on Tokyo and eight other prefectures was lifted, though looser restrictions remain in place until July 11.

Speaking to reporters at a vaccination centre, Suga said: "In the event a state of emergency was declared then we can't rule out not having spectators.

"I think that's obvious from the standpoint of making safety and security our utmost priority."

There were 376 new positive tests for COVID-19 reported in Tokyo on Sunday, an increase on the 304 a week prior. The seven-day average in the capital also rose to 388 from 384.1.

Tokyo 2020 president Seiko Hashimoto and Tokyo 2020 CEO Toshiro Muto are due to hold a news conference later on Monday after the culmination of talks surrounding domestic fans.