With the world fighting against an outbreak of the Omicron variant, China has been battling the pandemic in an orderly and methodical manner, said a leading infectious disease expert.

"It's important to stick to the current dynamic case-clearing strategy to fight against the resurgence of COVID-19 infections in a timely manner," said Zhang Wenhong, director of the infectious diseases department at Shanghai-based Huashan Hospital of Fudan University, through his Sina Weibo social media platform on Friday.

"In terms of the ongoing outbreak in Shangyu district, Shaoxing, Zhejiang province, as all the current cases were reported to have been located via clear transmission chains, it is only a matter of time before the final control of the outbreak, and no panic is called for," Zhang said.

Zhejiang reported 79 new cases on Friday, bringing the total number of COVID-19 cases in the latest outbreak to 423, with four new cases in Ningbo and no new cases in Hangzhou, the provincial capital. All cases were identified as infections of the highly-transmissible Delta variant.

Shaoxing, the hardest-hit city in the province, reported 75 new cases and one asymptomatic carrier on Friday. It added the city's total number of confirmed cases to 329 plus two asymptomatic cases.

Wang Hesheng, vice-minister of the National Health Commission, said in Shangyu on Thursday night that large-scale nucleic acid testing is vital to pinpoint and contain the sources of infection and cut off the channels of transmission in Shaoxing, local media reported on Friday.

Meanwhile community infections and the spread of COVID-19 cases are expected to be fully recorded by Monday in Shangyu, said an official with the local health commission.

"The closed-loop management of those who were in close contact with the infected patients can effectively help reduce the outbreak from spreading further," said Xia Shichang, vice-director of the Zhejiang Provincial Health Commission, on Thursday.

Sheng Jifang, director of the Department of Infectious Diseases at the First Affiliated Hospital of the College of Medicine at Zhejiang University, said vaccination has proven to be an effective way to keep patients' symptoms mild, and the next one or two weeks will be critical for the treatment of infected patients.

Fang Xiaoying in Hangzhou contributed to this story.