The gang shifted 300 kilograms (660 pounds) of drugs from northern Vietnam to the southern economic hub of Ho Chi Minh City between 2015 and 2016.

Five men and five women were given the death penalty after the trial this week in Hanoi, while two others got life in prison.

"The two ringleaders were paid hundreds thousands of dollars," for trafficking the drugs, local media reported.

Court officials could not be reached for comment on Friday.

The repeated haul of huge amounts of drugs is happening despite Vietnam having some of the world’s toughest drug laws. Those convicted of possessing or smuggling more than 600 grams of heroin or cocaine or more than 2.5 kg of methamphetamine could face the death penalty. The production or sale of 100 grams of heroin or 300 grams of other illegal narcotics is also punishable by death.

Last week police seized half a tonne of ketamine in Ho Chi Minh City and arrested three Taiwanese and one Chinese citizen in the bust.

That bust came just weeks after a similar haul of one tonne of crystal meth and around one tonne of ketamine in the city.

Many reports have noted that while heroin has long been common among drug users in Vietnam, the use of synthetic drugs like meth or ecstasy has been rising of late, especially among the partying youth.

Last September, seven people died of suspected overdose at a music concert in Hanoi.