Tokyo Olympics organisers said Wednesday they may put off an announcement on how many fans can attend the Games until May or June, as surging coronavirus infections play havoc with preparations.
Athletes are also likely to face daily virus testing, rather than once every four days as originally planned.
Organisers have already barred overseas fans from the pandemic-delayed Games, and were expected to announce an upper limit on domestic spectators sometime in April.
But Tokyo 2020 president Seiko Hashimoto said they are now only likely to "decide a direction" this month, and the decision could come as late as June - possibly just a month before the Games open on July 23.
The move would further delay ticket sales, which were put on hold when the Olympics were postponed last year.
"The Covid-19 situation is changing as we speak," Hashimoto said after organisers had reported to an executive board meeting of the International Olympic Committee.
"There are only 93 days left to go. We would like to make a proper judgement, and we may need more time in order to be able to do that."
"We need to carefully make a final decision about the spectators. The timing could be May or June," added Tokyo 2020 CEO Toshiro Muto.
Athletes are also likely to face a stricter testing regimen, as organisers prepare to release an updated version of their virus rulebooks "as soon as possible", Hashimoto said.
"In principle, tests will be conducted every day, but we are still in the process of taking the decision."
Test events delayed
Japan's latest rise in cases is causing further disruption for the postponed Games, with a number of test events delayed, cancelled or moved abroad.
In the latest upheaval, an artistic swimming qualifying competition has been moved from Japan, organisers said, and spectators will reportedly be barred from an athletics event at the main Olympic stadium.
The artistic swimming qualifier was originally set to take place in Tokyo in March before being rescheduled to May 1-4, but will now be held in June at "a location to be defined, outside Japan", organisers said late Tuesday.
World swimming governing body Fina said in a statement that "challenges related to the international calendar and the necessary adaptation of the venue to the Olympic Games operations" were behind the decision.
Fina has already rescheduled a Diving World Cup event in Tokyo and moved a marathon swimming Olympic qualifier from Japan to Portugal, amid reported dissatisfaction over virus countermeasures.
Japanese media said Wednesday that an athletics test event - which will double as a World Athletics Continental Tour Gold meet and feature athletes from overseas - will be held without spectators.
Organisers were set to allow 20,000 fans into the May 9 meet, according to Kyodo news agency, but tougher restrictions imposed by the Tokyo city government this month have forced a rethink.
Virus restrictions are expected to be tightened further this week, with Tokyo and several other regions seeking a state of emergency to tackle rising cases.
"Test events are a very important part of the preparation for the Games, so we want to hold them as scheduled," said Muto.
Despite the virus situation, Olympic organisers and local officials insist the Games can be held safely.
