A 2013 decree sanctioned only the sale of alcohol to underage people and not beer.
Beer establishments need to put up notices saying "Not to sell beer to people under 18 years old." Sellers are responsible for checking the age in case of suspicion a buyer might be underage.
The fines go up to VND3-5 million for selling alcohol and beer through vending machines or at banned locations such as educational and recreational establishments for people under 18.
Those hiring employees under 18 for the production and sales of alcoholic drinks will also be fined VND3-5 million.
The new decree comes in the wake of a law on mitigating the harmful effects of alcohol that took effect this year, stiffening penalties for drunk driving.
Last year Vietnam consumed more than 4.6 billion liters of beer, an increase of more than 10 percent from 2018.
The country spends an average $3.4 billion on alcohol each year, translating to $300 per capita, while spending on related health problems averages $113, according to the Ministry of Health.