Vietnamese police have seized some $3m US dollars-worth of heroin smuggled inside packets of tea, in the communist state’s largest ever drug case.

On Tuesday, Vu Chu Senh, 44, and his wife Mua Thi Do, 39, were caught by police in the northern Dien Bien province carrying 170 kilograms of heroin on their motorbikes.

Police believe the couple are members of a drug trafficking ring which bought heroin in Laos and transported the drug to Vietnam.

Vietnam has some of the world’s toughest anti-drug laws, with punishments ranging from stiff jail terms to capital punishment.

Anyone found guilty of possessing more than 600g of heroin, or more than 20kg of opium, in the country can face the death penalty.