Tulio de Oliveira, director of the Centre for Epidemic Response and Innovation (CERI) in South Africa, informed China's latest imposed limitations in Xi'an will not work.

"China will have great difficulty with Omicron and zero covid policy. They may need to join the rest of the world with mitigation strategies. #China should not punish its public health officials or citizens or foreigners because of a more transmissible variant," Oliveria tweeted.

Authorities in the Chinese city of Xi'an put an estimated 13 million residents under lockdown as 52 new Covid-19 cases were recorded in the region.

The sweeping restrictions, which prevent people from leaving their homes, come as the country braces for the Lunar New Year travel rush, followed by the 2022 Winter Olympics, due to begin in the capital Beijing on Feb 4, reports CNN.

The Chinese mainland on Sunday reported 162 new locally transmitted COVID-19 cases, the National Health Commission said in its daily report on Monday.

Of the new local cases, 152 were reported in Shaanxi, seven in Guangxi, and one each in Zhejiang, Guangdong and Sichuan, the commission said.

Also reported were 38 new imported cases in nine provincial-level regions, according to the commission.

Four new suspected cases arriving from outside the mainland were reported, and no new deaths from COVID-19 were reported on the day, it added.