The additional 10 percent tariffs slapped on Chinese imports by US President Donald Trump also apply to Hong Kong, officials say.

The confirmation came in a notice from US Customs and Border Protection.

The Hong Kong Trade Development Council (HKTDC) on Wednesday said the vast majority of goods from the SAR are now subject to the extra 10 percent tariffs, on top of regular and other potential extra duties.

Hong Kong is also affected by Washington's move to end the "de minimis" exemption that meant US shoppers didn't have to pay tariffs for shipments with a retail value of US$800 or less, the HKTDC said.

It noted that the US imported US$4.1 billion worth of goods from Hong Kong in 2023, with the duties paid totalling US$58 million.

"With the additional 10 percent duty in place, Hong Kong products would have faced US$411.6 million in additional duty liability in 2023, while mainland Chinese products would have faced US$42,081 million in additional duty liability," the HKTDC said.

The chairman of the Hong Kong Shippers' Council, Willy Lin, said he had been caught off-guard by Hong Kong's inclusion in the latest trade spat.

"Hong Kong customs and US customs do work very, very closely together to fight crime and fight drugs etc. We were quite surprised to see that Hong Kong was being labelled," Lin told RTHK.

"I think a 10 percent tariff is not really detrimental to Hong Kong, but it is reputation-wise," he said, adding that people will question why the SAR is being targeted.

In announcing the extra tariffs, Trump said China needed to stop the flow of fentanyl, a deadly opioid, into the United States.

Beijing has rejected accusations of complicity in the fentanyl trade and in response to Trump's move it has imposed tariffs of its own on multiple US products, while also announcing it would file a complaint with the World Trade Organization.