Tens of thousands of athletes, officials, games staff and media are arriving in Japan amid a local state of emergency and widespread opposition from the general public.

Events start on Wednesday - in softball and women's soccer - two days before the formal opening ceremony of an Olympics already postponed a year because of the coronavirus pandemic.

"The world is faced with great difficulties," Japanese Prime Minister Yoshihide Suga told International Olympic Committee members in a closed-door meeting at a five-star hotel in Tokyo, adding "we can bring success to the delivery of the Games".

"Such fact has to be communicated from Japan to the rest of the world.

"We will protect the health and security of the Japanese public."

He acknowledged Japan's path through the pandemic toward the Olympics had gone "sometimes backward at times."

"But vaccination has started and after a long tunnel an exit is now in our sight," Suga said.

Health experts in Japan have questioned allowing so many international visitors for the Games, which end on August 8.

There will be no local or foreign fans at events.

About 85 of the 101 IOC members were in the room for their first in-person meeting since January 2020.

Their previous two meetings, including to re-elect Bach in March, were held remotely.

One member missing the meeting, Ryu Seung-min of South Korea, tested positive for COVID-19 after arriving on a flight on Saturday.

Bach has been met with anti-Olympic chants from protesters on visits in Japan since arriving two weeks ago, including at a state welcome party with Suga on Sunday.

The IOC leader praised his hosts on Tuesday, saying "billions of people around the world will follow and appreciate the Olympic Games".

"They will admire the Japanese people for what they achieved," Bach said, insisting the Olympics will send a message of peace, solidarity and resilience.

Cancelling the Games was never an option, according to Bach, because "the IOC never abandons the athletes".

Bach said the IOC is contributing $1.7 billion ($A2.3b) to Tokyo organisers of the Olympics and the Paralympics.

The Paralympics will follow in late August.

Australian Associated Press