The Tokyo metropolitan government on Wednesday confirmed 55 new coronavirus infections in the capital, an official said, marking the highest number of daily cases since early May.

The figure is the largest since May 5, when the Tokyo government reported 57 cases, with two deaths confirmed Wednesday.

The latest development has reignited concerns of a fresh wave of infections, with new cases gradually increasing since late May and staying around or above 30 in the past week. Tokyo has seen more cases whose routes of infection are untraceable.

The discovery of the new cases brought the total number of coronavirus infections in the capital to 5,895, the most among Japan's 47 prefectures, with deaths totaling 325.

Tokyo needs to pay close attention to whether the number of cases with untraceable infection routes will increase, Takaji Wakita, head of a government panel tasked with measures against the coronavirus, told a press conference.

"We are closely monitoring whether the situation will turn into a second wave (of infections)," he said.

Of the 55 cases, nine people in their 20s were reported from a workplace where seven people had tested positive earlier, and 20 from the nightlife industry, including 12 confirmed in group testing conducted by Shinjuku Ward, according to the Tokyo government. The ward has been carrying out intensive testing following the recent rise in new cases in the Kabukicho entertainment district.

"It is an example of how group infections can occur at a workplace," Tokyo Gov. Yuriko Koike told reporters, in reference to the nine people. "I want people to reconfirm their way of working" in accordance with measures against the coronavirus.

The governor added it is hard for authorities to grasp how thoroughly preventive steps are implemented at offices, as a large number of people are returning to work following the lifting of the state of emergency over the pandemic in late May.

New infections in Tokyo had been on a declining trend through late May. But they rebounded after the state of emergency was lifted on May 25 for the last batch of prefectures, including Tokyo.

The country last week lifted its final advisories on inter-prefectural travel. Businesses have also reopened.

On Friday, the Tokyo metropolitan government withdrew its temporary closure request on all businesses by lifting the last-remaining request on live music venues, nightclubs and similar entertainment establishments where people come into close contact in enclosed spaces.

It was the last phase of the Tokyo government's three-step restriction easing process.