The movement of Aere typhoon as forecast by Hong Kong Observatory.
Fishermen have been told to take cover with wind speeds of up to 100kph forecast.
Tropical Storm Aere strengthened from a depression on Thursday and is heading towards northern and central Vietnam with wind speeds of up to 100 kilometers per hour.
The Central Hydrometeorology Forecasting Center said the storm in the South China Sea, known as the East Sea in Vietnam, is heading northwest at 20-25 kilometers per hour and gaining in strength. Sustained winds on Friday will hit 90kph and 100kph on Saturday.
Fishing boats in Quang Ninh Province, home to the popular Ha Long Bay, down to Khanh Hoa Province, home to the resort town of Nha Trang, have been asked to prepare to take shelter.
The southern region will also be affected as the storm combines with strong monsoon winds to cause thunderstorms from Binh Thuan Province down to the Mekong Delta, where waves at sea may peak at 2.5 meters.
Aere is the sixth major storm to form along Vietnam’s eastern coast this year, and experts say there are likely to be a couple more before the season ends.
An average of eight to 10 tropical storms hit Vietnam between July and October every year, often causing heavy human and material losses.