Hidemasa Nakamura, delivery officer for Tokyo 2020, conceded the city's battle against coronavirus had "deteriorated" since the start of the Olympics, raising further question marks over the staging of the Paralympics.

Japan topped 25,000 new coronavirus cases in 24 hours for the first time yesterday despite much of the country, including Tokyo, being under a state of emergency.

On the eve of the Opening Ceremony of the Olympics on July 23, Tokyo registered nearly 2,000 COVID-19 infections.

Almost one month later, Tokyo totalled more than 5,000 cases for a third straight day, with 5,405 reported over the past 24 hours.

The Paralympics are due to open next Tuesday (August 24) with around 4,400 athletes from across the world set to compete largely behind closed doors.

After holding a meeting with experts on COVID-19 countermeasures, Nakamura admitted more needed to be done to protect athletes from catching the virus.

"Para athletes compared to Olympic athletes have the risk of getting an even serious symptom, so we need to be even more careful," said Nakamura.

"The infection state is different to how it was for the Olympics.

"It has deteriorated and the local medical situation is tight.

"The Olympic COVID-19 countermeasures will be continue to be followed but additional measures will be required."

According to a report by Japanese newspaper Asahi Shimbun, a hospital in Tokyo rejected a request from Paralympic organisers to offer emergency care for serious cases.

Yuichi Hamabe, who heads the Tertiary Emergency Medical Center of the Tokyo Metropolitan Bokutoh Hospital, said it was "unthinkable to accept such a request when a response at the level of a natural disaster is required to contain the spread of the virus".

"The Organising Committee made the request just before the Paralympics kick off," said Hamabe.

"That shows it doesn’t think Games can be held safely.

"Concerned parties should quickly discuss whether to go ahead with the Paralympics."

Nakamura conceded that the "limitations" in the capacity of hospitals had presented extra challenges for organisers to overcome.

"Even in today’s roundtable, a couple of doctors mentioned that given the current medical situation we are going to have to have this Paralympic Games in a very difficult situation," said Nakamura.

"If a serious symptom were to occur we would need to have contact flow in line and we also need to include the hospitals and medical facilities in that flow of contact.

"It’s really a matter of time.

"It’s a fight against time so we need to make sure that sufficient communication is taken at a speedy manner."