The container was found to contain 1,266 kilogrammes of ivory hidden under packages of peanuts listed on the bill of lading, Pham Manh Tu, customs chief of the northern port city of Hai Phong, told dpa.
"We discovered the ivory through our investigation and surveillance work," he said. Each of the tusks, which were found Tuesday, were cut into three or four pieces.
The container was addressed to an import export company in Quang Ninh province, which refused the shipment and denied all knowledge of it.
Ivory is banned from import or export in Vietnam. The biggest seizure to date in Vietnam was in March 2009 when customs agents in Hai Phong found more than six tonnes in a container shipped from Tanzania.
According to the World Wide Fund for Nature, most ivory smuggled into Vietnam is destined for China but some is sold locally for $770-$1,200 per kilogramme.
International trade in ivory has been banned since 1989 with the exception of occasional auctions from stockpiles.