The six, who work at the Bac Sinh Phong Border Gate, have been suspended for 15 days pending an investigation, according to Vietnam Customs.
On December 17, the local police found a number of container trucks carrying smuggled goods in Hai Ha District, and by checking the warehouses they were headed for, they found the 300 tons of contraband.
Most of it was clothes, cosmetics, auto parts, motorbikes, and electronic products.
The police arrested 30 people including alleged linchpin Dao Van Chap, 51. They said the group admitted to bringing around 200 tons of goods into the country daily.
Officials called it a large organized smuggling operation that involves people in many parts of the country.