Vietnam customs officials have seized nearly one tonne of ivory hidden in a timber shipment from Kenya, an official said Thursday, the third major illegal haul of precious tusks in less than a month.



The communist nation is a popular transit route for illegal ivory from Africa heading to other parts of Asia, namely China, where it is used for decorative and medicinal purposes.



Ivory products are also hot in Vietnam, though the trade is officially banned.



The latest haul from Kenya was discovered at a port in Ho Chi Minh City on Wednesday, where it was carefully hidden in a shipment of timber logs -- a common practise among smugglers.



Some 3.5 tonnes of ivory have been discovered at the city's Cat Lai port this month, all in crates of wood, including a hefty two-tonne haul packed into a single shipment.



"All that ivory was not just to be consumed in Vietnam," a customs official told AFP, requesting not to be named.



"We believe much of it was to be later be transferred to the main market, China."



This week's cache reportedly originated in Kenya's Mombasa port and was sent to Malaysia's Tanjung port before arriving in Vietnam, according to state-run Thanh Nien newspaper.



Vietnam outlawed the ivory trade in 1992, but shops still sell ivory dating from before the ban and weak law enforcement has allowed a black market to flourish.



A two-week survey by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) last year found out that more than 16,000 ivory products were available in Hanoi.



Vietnam is hosting an international conference on illegal wildlife trade from November 17 to 18, which will be attended by Britain's Prince William, a vocal critic against illicit wildlife trafficking.