As the world's biggest economies threaten a trade war, most economists and business leaders are optimistic cooler heads will prevail. But among China's Asian neighbours, especially in Asean, the risk is real that trade with their neighbour will stall.

"Many companies are currently assessing their supply chains based on different scenarios," said Mr Adam Sitkoff, executive director of the Vietnam chapter of the American Chamber of Commerce in Hanoi. "I remain hopeful that Washington and Beijing will not follow through on their threats."