14 of the cases were detected in Bac Giang, 7 in Dien Bien, 5 in Ha Nam and 2 in Lang Son.
The cases in Bac Giang, Dien Bien and Ha Nam were in contact with previously confirmed coronavirus cases and the cases in Lang Son are workers at Japanese electronics company Hosiden, a coronavirus hotspot.
The latest cases have brought the national count since Monday morning to 67.
On Monday morning Vietnam confirmed its 37th COVID-19 death. The Ministry of Health said the 34-year-old man from Bac Ninh province died of severe pneumonia due to COVID-19, brain injury related to an earlier accident, and meningitis.
Vietnam has been coping with a new COVID-19 wave that broke out on April 27 and has so far seen more than 1,200 cases nationwide.
Nearly 1 million people in Vietnam have been inoculated against COVID-19, with more than 22,000 getting two shots, according to the Health Ministry.