The arrests were made after monitoring a local man, Dinh Van Tu Anh, they said Tuesday.
The Go Vap District police had in March discovered drug dens Anh ran at several locations.
They raided all of them and took in 26 people for questioning and seized nearly 40 kg of narcotics hidden in food cans.
Expanding the investigation, they identified similar people related to those Go Vap's dens in Tan Phu and Tan Binh districts and arrested a further 60 people and seized four kilograms of drugs, grenades, ammunition, and three guns.
They determined that the drugs were smuggled into Vietnam by the gang in food cans.
The investigation is being expanded, the police said, without providing any more information about Anh or the timeline of their arrests.
Vietnam has some of the world's toughest drug laws. Those convicted of possessing or smuggling more than 600 grams of heroin or cocaine or more than 2.5 kg of methamphetamine face the death penalty.