Elephant tusks worth more than $1 million were seized by Hong Kong customs after being discovered hidden under bags of soya in shipments from West Africa, officials said Thursday.

In what officials called an "intelligence-based" operation last month, the southern Chinese city's border control found 189 tusks in three containers.

"After X-ray examination, the officers found the ivory tusks, weighing 769 kilogrammes (1,695 pounds) in total, in the innermost parts of the containers. The ivory tusks were packed in linen and nylon bags and covered by bags of soya," a Hong Kong government spokesman said in a statement released Thursday.

The three six-metre (20-foot) containers arrived at the city's maritime port from Cote d'Ivoire in separate shipments, according to customs officials, who did not specify when the shipments arrived.

They said the tusks could be sold for HK$11.53 million ($1.49 million).

The seizure came less than two months after the last major haul of 1,000 elephant tusks found in a container from Nigeria, which along with rhino horns and leopard skins also discovered was worth more than $5 million.

Ivory is popular with Chinese collectors who see it as a valuable investment and leopard skin is a popular material for fashion and decoration.

"Hong Kong...is committed to continuing to take vigorous enforcement action against the trafficking of endangered wildlife," Hong Kong customs head of ports and maritime command, Vincent Wong, said in the press statement.

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

Hong Kong, a free port which runs one of the biggest container terminals in the world, often sees the seizure of products from banned trades.

But customs officials have previously said there was "no concrete information" to show that the financial hub had become a gateway for ivory smuggling.