At least eight people have died after attending a funeral party in the mountainous province of Lai Chau on Saturday last week.
Police said they suspect food poisoning to be the cause, but have noticed no signs of foul play.
Several others are still being treated at a local hospital.
The party was held by a local family from Saturday to Monday to mourn a recently deceased family member.
Victims said they all drank wine bought from a commune on the Chinese border and Chinese candy was also served at the party. Then they all suffered from nausea and stomachaches.
Six people between 35 and 55 years old died on Monday. Authorities have confirmed two more deaths on Tuesday.
Police are testing food and drink samples and will conduct forensic examinations to identify the cause of death.