29 cases were recorded in Bac Ninh and two in Ninh Binh.
Two of the cases in Bac Ninh are workers from its neighbor Bac Giang's Quang Chau industrial park, which has all been shut down as a coronavirus hotspot, while 19 had close contact with previously confirmed Covid-19 patients and eight others were detected in an already isolated area.
In Ninh Binh, two cases are those in affected areas that have been isolated.
Since the new wave of Covid-19 emerged in Vietnam on April 27, the nation has recorded 2,067 cases in 30 cities and provinces, including six deaths.
Bac Giang and Bac Ninh, both housing major foreign manufacturing plants, are leading the case count with 851 and 448 infections.