Malaysian customs have seized 24 tonnes of unprocessed elephant tusks worth almost $20 million, the largest haul in the country to date, officials said Tuesday.

Some 1,500 tusks hidden in two containers were discovered by customs officials at the country's main port of Klang, in the western state of Selangor.

The tusks had been hidden within pieces of timber inside the containers, which had originated from the west African nation of Togo.

State customs director Azis Yaacub said in a statement that the cargo had been transferred from one ship to another in Spain and was believed to be headed to China.

"The two containers were found to be filled with sawn timber. Inside the wood there were secret compartments that were filled with elephant tusks," he said.

The haul is worth 60 million ringgit, which amounts to $19.6 million. Officials said that the seizure on December 7 was the fourth in the past year and was larger than the other three combined.

Wildlife trade-monitoring network TRAFFIC has described Malaysia as a major hub for illicit wildlife products.

International trade in elephant ivory was banned in 1990 with rare exceptions, such as auctions of tusks from elephants that have died naturally, or that have been seized from poachers in Namibia, Botswana and South Africa.

However, the ivory trade has grown globally since 2004, largely due to demand in China, where it is used in traditional medicine.

According to the World Wildlife Fund, African elephant populations may have been as high as five million in the first part of the 20th century, but their numbers could now be as low as 470,000.