Most of the new cases were detected in Ho Chi Minh City, at 965, marking the first time in over a month that the city has got less than 1,000 cases per day.
It is followed by Can Tho City in the Mekong Delta with 898 cases and the southern Tay Ninh Province with 869 cases.
Hanoi reported 737 cases on Tuesday, marking the highest number of infections it has ever recorded in a single day.
In the past 24 hours, 217 Covid-19 patients have died, including 57 in HCMC, with four of them transferred to the city from other provinces.
Since the pandemic started last year, the death toll in Vietnam has climbed to 26,700, or 2 percent of all infections.
In the latest wave that hit the country in late April, more than 1.33 million cases have been confirmed and over one million of them have recovered.
So far, 55 million people have been fully vaccinated.