The provincial Economic Police Department said it had launched criminal proceedings against Do Xuan Luan, 44, of Hai Son Commune, on charges of smuggling.
Authorities searched Luan's residence on May 8 following suspicions that he was storing smuggled goods.
During the inspection, officers found 130 sacks containing a total of 518 metal canisters filled with nitrous oxide, commonly known as laughing gas.
Investigators said Luan allegedly decided to import the canisters after seeing strong market demand for the product.
According to police, he contacted a Chinese supplier in late April and agreed to purchase the 518 canisters at VND 290,000 (USD 11) each.
Police said the shipment was delivered by raft across the border near Border Marker 1352 in Hai Son Commune. Luan allegedly transported the canisters to his home and stored them in a warehouse pending sale.
Authorities said the entire shipment lacked documents proving its legal origin.
All canisters and related items have been seized as evidence.
The case is under further investigation.