The Civil Aviation Authority of Vietnam (CAAV) said the measures were introduced in line with regulations issued by the International Civil Aviation Organisation (ICAO).
Under the new rules, passengers may carry no more than two power banks, which must be transported in carry-on baggage rather than checked luggage.
Power banks containing lithium metal batteries must not exceed 2 grammes of lithium content, while lithium-ion power banks must have a rated capacity of no more than 100 watt-hours (Wh).
Devices with a capacity exceeding 100Wh but not more than 160Wh may only be carried with prior approval from the airline.
Passengers must remove power banks from their bags and place them in a visible location during flights. The devices must not be used to charge electronic equipment or be recharged while on board.
The CAAV also requires power banks to be individually protected against short circuits, either by using the manufacturer's retail packaging, insulating exposed terminals or storing each device in a separate plastic bag or protective pouch.
Airlines have been instructed to strengthen communication with passengers about the new requirements.
