The National Health Commission on Monday reported 223 new confirmed Covid-19 cases for January 16, up from 119 a day earlier.
Of the new infections, 163 were locally transmitted, according to the mainland's health authorities, up from 65 a day earlier.
It said the new locally transmitted cases were in Tianjin, Henan, Guangdong, Shaanxi and Guangxi.
The country also reported 28 new asymptomatic cases for Sunday, which it classifies separately from confirmed cases, down from 52 a day earlier.
The figures were released as the Lunar New Year travel season started on Monday, with an increasing number of Chinese cities on high Covid alert.
Luoyang in Henan and Jieyang in Guangdong now say anyone wanting to travel has to report the trip three days ahead of arrival, while Yulin in Guangxi says a digital form - with health credentials and trip details - must be filed in a day in advance.
Over the weekend, Beijing announced stricter testing for arrivals after confirming its first local Omicron case. Some schools in the capital have also closed early and moved classes online ahead of the winter holidays.
Shenzhen has also been added to the list of places where the new coronavirus variant has spread, while Zhuhai reported two more locally transmitted coronavirus cases on Sunday.
So far, at least five provinces and municipalities have reported local Omicron infections, while 14 have found the variant among travellers arriving from overseas.
The first cases of the highly-contagious Covid variant were confirmed just over a week ago in Tianjin. (Reuters)