In a communication sent to relevant agencies on Friday, deputy chairman of its People's Committee, Duong Anh Duc, said the number of cases has been rising slightly in the city since the beginning of April.
The presence of the highly contagious Omicron variant XBB.1.5 has been detected, he warned.
The administration wants them to deploy preventive measures and monitor the situation to prevent outbreaks.
They include vaccination, especially for high-risk populations, and ensuring medicine and equipment are on standby to prevent infections and deaths.
The public is required to wear masks inside medical facilities, public transport vehicles and at crowded events and locations.
Schools in particular are considered high-risk locations, and so are required to have prevention measures and inform health authorities when cases are detected.
Since the beginning of March HCMC has recorded one new Covid case a day on average.
But the number has increased slightly this week, with three cases found on April 12 and seven on April 13.