Vietnamese customs officials said that “dozens” of products have been identified as having been subject to the fraud.
Donald Trump has railed against China’s trade surplus with the US, imposing new tariffs on billions of dollars worth of goods in an attempt to redress the imbalance.
The tariffs have sparked a trade war, with the Chinese government imposing retaliatory tariffs worth comparable amounts on exports from the US.
Chinese firms are now thought to be exporting goods including textiles, farm products, tiles, honey, iron, steel, and plywood via Vietnam, where a Vietnamese certificate of origin can be applied for.
In one instance, a Vietnam-based firm was found by US customs officials to be importing Chinese timber products, relabelling them, and then exporting them to the US.
Vietnamese foreign minister Pham Binh Minh reacted furiously to revelations of the practice, saying: “It will sabotage Vietnamese brands and products and it will also affect consumers.
“We could even get tariff retribution from other countries, and if that happens, it will hurt our economy.”
The Vietnamese government added that more stringent checks would be put in place on exports to the US, Europe, and Japan.