A court in Quang Ninh Province said traffic police in Ha Long Town near the China border stopped Lao man Chittakone Luangaphay, 34, and Phung Trung Dung, 43, on March 29 last year and found the heroin hidden inside the vehicle and two bags of methamphetamine on Dung.

The duo said they had been hired by two Lao men to carry the heroin from the Laotian capital Vientiane to Quang Ninh in northern Vietnam.

Dung said one of the meth bags was from the Lao men as a "gift to help me stay awake" during the long trip. 

The plan was to reach Ha Long and for Luangaphay to contact customers and Dung to deliver the drugs.

Luangaphay said he had carried out a similar mission earlier, carrying two suitcases of meth from Laos to Da Nang in central Vietnam. He got paid $2,000 for that.

Cases of Laotians getting caught and sentenced for carrying drugs into Vietnam are not rare.

A Lao man was caught on Sunday with 60,000 ecstasy pills in the border province of Quang Tri. Another was sentenced to death last month for carrying 300 kilograms of meth into Vietnam.

Vietnam is a key trafficking hub for drugs from the Golden Triangle, an intersection of Laos, Thailand and Myanmar, which is the world's second largest drug producing area after the Golden Crescent in South Asia.

Drug trafficking and consumption have persisted and worsened in Vietnam in the last few years despite it having some of the world's toughest anti-drug laws, including death for smuggling and trading.