Japan's daily total of COVID-19 cases surpassed 14,000 on Wednesday, setting another record just days after hitting the previous high, as concerns grew over the strain on the medical system in Tokyo, where the Olympics are being held.

The capital, struggling to contain a resurgence of the coronavirus despite being under its fourth pandemic state of emergency since July 12, confirmed a record 4,166 daily coronavirus cases.

Ten other prefectures, including neighboring Saitama and Chiba, also logged new records the same day.

Japan reported record single-day figures for five consecutive days through Sunday, when it logged more than 12,000 cases.

The government of Prime Minister Yoshihide Suga is considering placing eight prefectures including Fukushima, Tochigi and Aichi under a quasi-state of emergency from Sunday to the end of the month due to growing cases of infections, people close to the premier said. A decision is expected on Thursday.

Some of those prefectures have asked the government for the quasi-emergency entailing business restrictions similar to the state of emergency but with smaller penalties for non-compliance.

According to the National Institute of Infectious Diseases, the highly contagious Delta variant of the coronavirus made up 90 percent of infections in the Kanto region in eastern Japan, including Tokyo, and 60 percent in western Japan as of early August.

Tokyo's latest tally topped 4,058 cases reported on Saturday. The capital's seven-day rolling average of infections also rose to a record 3,478.7 per day, up 78.0 percent from the previous week.