T2 will be built by the Airports Corporation of Vietnam (ACV), which operates all 22 commercial airports in the country, at a cost of VND2.4 trillion ($102.75 million) and can handle five million passengers a year, according to a decision signed by Deputy Prime Minister Le Van Thanh Friday.
Once completed, it will handle domestic services while the existing T1 will become the international terminal.
The construction has a deadline of 18 months from the time the ACV receives the required land from city authorities.
T2 will also have a hangar and wastewater treatment plant.
Hai Phong has been seeking another terminal for Cat Bi since 2018 after T1 began to show signs of overloading.
The airport serves 4-5 million passengers a year.