Tokyo reported 21,122 new COVID-19 cases on Saturday, the second-highest daily tally on record, the metropolitan government said, as the highly transmissible Omicron variant continues to spread rapidly across Japan and lead to an increase in seriously ill patients.

The figure came after the Japanese capital recently confirmed a record 21,576 new coronavirus cases, and as Tokyo remains under a quasi-state of emergency amid its sixth wave of infections driven by Omicron, with concerns over infections among young people spreading to other family members.

Tokyo recently unveiled a set of new benchmarks to be considered when requesting a COVID-19 state of emergency, such as if the rate of hospital bed occupancy secured for COVID patients with serious symptoms or the percentage of COVID patients needing oxygen supply has reached a threshold of 30 to 40 percent.

The new guidelines were laid out as Tokyo aims to strike a balance in preventing the medical system from being burdened and further affecting economic activity.

At a monitoring meeting Thursday, the metropolitan government also raised the alert on its four-tier scale on the medical system to the highest level, meaning the system is "under strain."

Although 35 of Japan's 47 prefectures, including Tokyo, have been placed under the quasi-state of emergency measures, nationwide daily COVID-19 cases remained high, with Saturday's figure at 102,371, again topping 100,000 since first reaching that level on Thursday.

The latest figure has pushed the cumulative total past 3.2 million, according to a Kyodo News tally based on local government releases.

Other areas, including Kanagawa and Saitama near Tokyo, as well as Fukuoka and Hokkaido, saw record daily coronavirus figures.

On Saturday, the health ministry said the number of COVID-19 patients with serious symptoms stood at 1,099, surpassing 1,000 for the second straight day and marking a jump from the 51 reported on New Year's Day.

The country also reported 117 deaths on Saturday, topping 100 for two days in a row.

Shigeru Omi, the government's top COVID-19 adviser, expressed concern over a potential rise in deaths and seriously ill patients, telling reporters on Saturday, "Infected young people are spreading the virus to the elderly, thus increasing the number of elderly patients."