Vietnam has seized two tonnes of illegal elephant tusks found stashed in bags of shells being shipped to China, state media reported Wednesday.

Customs officials found the tusks in a shipping container that had been transported to the northern port city of Hai Phong from Malaysia, according to the state-run Tuoi Tre newspaper.

"The shipment is supposed to be transferred by road to the Lang Son border gate, heading for China," it added, without specifying when the tusks had been discovered.

The report did not give the value of the shipment, but a haul of 769 kilos (1,695 pounds) of ivory tusks in Hong Kong last week had an estimated sale price of $1.49 million, according to the city's customs officials.

Elephant tusks and other body parts are prized in both China and Vietnam for decoration, as talismans, and for use in traditional medicine.

The international trade in ivory, with rare exceptions, has been outlawed since 1989 after the population of African elephants dropped from millions in the mid-20th century to just 600,000 by the end of the 1980s.

More than 25,000 elephants were poached last year, according to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).

Environmental group WWF says communist Vietnam is one of the world's worst countries for trade in endangered species.

The country outlawed the ivory trade in 1992 but shops can still sell ivory dating from before the ban.