Customs official Truong Cong Thanh in the northern port city of Hai Phong says the tusks were found in a container yesterday. The cargo had been declared as sea shells. Thanh said today that the case was under investigation.
Earlier this month, customs officials in Hai Phong had seized nearly 2 tons of tusks also smuggled in from Malaysia.
The tusks were to be used for jewelry and home decorations.
Vietnam bans hunting of its own dwindling population of elephants, which poachers value highly for their tusks.