Customs officials at the Noi Bai International Airport in Hanoi were suspicious of the plaster blocks that came in a shipment categorized as exempt from examination.
They broke open the blocks with hammers and discovered the rhino horns inside.
Documents show the shipment was sent from UAE to a recipient in Bac Giang Province, the Yang Shin Limited Company. The Thien Ha Garment and Export Trading Co., also based in the northern province, was identified as the declarer of the shipment.
There was no information available on what the stated purpose of the plaster blocks was.
All the horns have been confiscated and an investigation launched.
The sale and purchase of rhino horns is strictly banned in Vietnam, but the country remains one of its biggest consumers, with people believing it has near-miraculous powers of curing diseases like cancer.
Vietnam's last Javan rhino, a rare Southeast Asian species, was found dead in 2010 with its horn hacked off.