Police in the northern port city said they found 386 customers and employees at the Dom Club in Ngo Quyen District. Of these, test results made available Monday showed that 153 people had consumed narcotic substances.
Dom Club, Hai Phong's biggest dance club, obtained its discotheque business license in 2015.
Local officials had shut the place down on October 29 for 30 days until November 28 because of problems with fire prevention.
However, the club was operating normally when the raid took place.
Despite Vietnam’s very tough laws against drug production and trafficking, the country has emerged as a key trafficking hub for narcotics from the Golden Triangle, an intersection of China, Laos, Thailand, and Myanmar that is the world's second largest drug producing area after the Golden Crescent in South Asia.