China has reported 206 new Covid-19 cases, including 158 domestically transmitted ones, in a sudden spike ahead of the Beijing Winter Olympics which will be held in February next year, the country's health commission said on Sunday.

Of the new local cases of coronavirus, 157 were reported in Shaanxi and one in Guangxi provinces, besides 48 imported cases, the National Health Commission (NHC) said.

The spike in cases ahead of the 2022 Beijing Winter Olympics has sparked concerns in the country as officials scampered to arrest the spread.

Though China has controlled the contagion by drastically limiting international travel, sporadic clusters of cases continued to surface in different parts of the country, putting its Zero case policy under stress.

Chinese officials reported a case of Omicron on December 13 in Tianjin city followed by a few more cases. However, there is not much information about its spread in the country.

The health officials also reported an outbreak of Delta strain sub-lineage AY.4 in Zhejiang province in the middle of the month which was reportedly brought under control.

There were 2,011 active cases in China as of Saturday, with nine in critical conditions, the commission said.

No new deaths related to the disease were reported, while 76 patients were discharged from hospitals on Saturday, it added.

The total number of cases on the Chinese mainland stood at 101,077 since the virus broke out in Wuhan in 2019 with the death toll unchanged at 4,636.

The Beijing Winter Olympics, the 24th edition of the showpiece that started way back in 1924, will be held from February 4 to 20.