The new cases onWednesday exceeded the earlier record of 2848 set the previous day and bring the total for the Japanese capital to 206,745 since the pandemic began early last year.

Tokyo has been under a fourth state of emergency since July 12 ahead of the Olympics, which began last Friday despite widespread public opposition and concern that they could further worsen the outbreak.

Experts say Tokyo's surge is being propelled by the new, more contagious delta variant of the virus.

Tokyo Governor Yuriko Koike on Wednesday urged younger people to cooperate with measures to bring down the high number of infections and get vaccinated, saying their activities are key to slowing the surge during the Olympics.

Koike noted that the majority of the elderly have been fully vaccinated and infections among them have largely decreased, while the mostly unvaccinated younger people are now dominating the new cases.

"Younger people's activity holds the key (to slowing the infections), and we need your cooperation," Koike said.

"Please make sure to avoid non-essential outings and observe basic anti-infection measures, and I would like younger people to get vaccinated."

As of Tuesday, 25.5 per cent of the Japanese population had been fully vaccinated. The percentage of the elderly who are fully vaccinated is 68.2 per cent, or 36 million people.

There are concerns over vaccine hesitancy among the young, with surveys showing many of them having doubts, in part due to fake rumours about side effects.

Australian Associated Press