Shenzhen, Guangdong province, has made an initial success in curbing the latest coronavirus outbreak, a local health official said.

"Most of the new cases in recent days were found in people who had close contact with confirmed cases or key groups under centralized isolation and medical observation," said Lin Hancheng, an official of the city's health commission.

As of Monday, the city had reported 165 positive test results since Feb 15, the commission said.

On Monday alone, 28 new cases were reported in Shenzhen. Of those, 23 were confirmed and five were asymptomatic carriers, the commission said.

New cases were mostly concentrated in the city's downtown Futian and Nanshan districts after Feb 20, Lin said.

"The next few days will be the most critical period for us to fight the outbreak," Lin said, calling on local residents to continue their prevention and control measures.