The Tuoi Tre newspaper said today that customs officials in the northern port city of Hai Phong discovered the tusks last week in a container shipped from Malaysia that had been declared as sea shells that were transiting to China.
Customs officials were not immediately available for comment.
In 2009, authorities in Hai Phong confiscated nearly 7 tons of ivory smuggled from Tanzania in the country's biggest such seizure.
The tusks were to be used for jewelry and home decorations.
Vietnam bans the hunting of the country's dwindling elephant population, which poachers value highly for their tusks.