TOKYO (REUTERS) - Athletes arriving in Tokyo for next year's Olympic Games, postponed from 2020 because of the coronavirus pandemic, will be exempt from the 14-day isolation period Japan has imposed on anyone arriving from overseas to help stop the virus spreading.

Olympic organisers said on Thursday (Nov 12) details still need to be worked out, but measures for athletes are likely to include coronavirus testing within 72 hours before arriving in Japan. But they warned decisions on spectators from overseas have yet to be made, saying a 14-day quarantine was "impossible".

"Athletes, coaches and Games officials that are eligible for the Tokyo Games will be allowed to enter the country, provided significant measures are made before they get to Japan," Tokyo 2020 chief executive officer Toshiro Muto told a news conference.

He was speaking after a meeting between officials from the Tokyo Metropolitan Government, the national government and Tokyo 2020 organisers on infection prevention procedures during the Games.

He said a decision on foreign spectators would be made next year, depending on pandemic developments.

"By next spring, we will be coming up with a plan for spectators, including non-Japanese spectators," he said. "It is impossible to set a 14-day quarantine period for foreign spectators, so tests before and upon arrival are needed."

Japan has held several recent test events, including a four-nation gymnastics meet last weekend, in which 2,000 socially distanced spectators were admitted, but these were limited to residents of Japan.

International Olympic Committee head Thomas Bach is due in Japan for a three-day visit next week, at which Muto said he expected details of coronavirus counter-measures would be ironed out.

"It (the trip) is important because we are now coming to a crucial stage of putting this toolbox together with Covid-19 counter-measures to get the feeling what will be needed next year," Bach told a news conference on Wednesday, ahead of his Nov 15-18 visit.

"I hope after this visit we can give even more confidence to all the participants of the Games about the safe environment they will see in about nine months from now."

The IOC and Japanese organisers took the unprecedented decision in March to delay the Games by a year to 2021 due to the pandemic, a costly postponement that still has many moving parts given the spread of the virus.

Bach said it was still to early to say whether spectators or even international visitors would be part of the Olympics in July and August but he believes recent events held in Japan such as the gymnastics meet provide confidence that some fans will be in the arenas.

"(The IOC is) more and more confident that we will have a reasonable number of spectators," Bach said. "How many and under which conditions, again, depends very much on the future developments.

"The message I want to deliver in Tokyo is that we are fully committed to the safe organisation of the Games. This is the principle to which we remain committed; that these Games will happen in a safe environment."