Vietnam and the United States have started talks "on bilateral economic and trade issues" in the wake of threatened US tariffs, Hanoi said.

US President Donald Trump this month threatened massive 46 percent levies on Vietnam, with Washington accusing the country of facilitating Chinese exports to the United States and allowing Beijing to get around tariffs.

Vietnam's minister of industry and trade Nguyen Hong Dien had a phone call late Wednesday with US Trade Representative Jamieson Greer, the ministry said in a statement posted on its website after the meeting.

"This is an important meeting to discuss the issues of principles, scope and roadmap for negotiations," said the statement.

The United States was Vietnam's biggest export market in the first three months of the year.

Vietnam's trade ministry has ordered authorities to tighten control over the origin of goods to avoid sanctions, according to a document seen by AFP.

China's President Xi Jinping urged the communist neighbour to join forces in upholding free trade during a visit to Vietnam last week.

Beijing also said it "firmly opposes" other countries making trade deals with the United States at Beijing's expense, warning it would take "countermeasures" against them.

Vietnam was Southeast Asia's biggest buyer of Chinese goods in 2024, with a bill of $161.9 billion.

The country's Prime Minister Pham Minh Chinh has said that any talks were "not to affect another market".

During the phone call, Dien reiterated Vietnam's readiness "to negotiate and resolve issues of concern to the United States, and to find reasonable solutions for mutual benefit, in the spirit of harmonious interests and shared risks".

The statement quoted Greer as saying he believed the two sides "will soon reach appropriate solutions, promoting stable and mutually beneficial economic and trade relations".

Vietnam has long pursued a "bamboo diplomacy" approach -- striving to stay on good terms with both China and the United States.