US President Donald Trump signed an executive order on Wednesday that closes a trade exemption known as "de minimis" that has allowed low-value packages from mainland China and Hong Kong to enter the United States, free of duties.

Trump signed the order, which takes effect on May 2, in the Rose Garden of the White House after announcing sweeping new tariffs on global trading partners.

The White House said the move came after Commerce Secretary Howard Lutnick certified "adequate systems are in place to collect tariff revenue" on the shipments.

It said imported goods from mainland China and Hong Kong sent outside the international postal network and valued at or under US$800 would now be subject to all applicable duties.

Imported goods sent through the postal network and valued at or under US$800 would now be subject to a duty rate of either 30 percent of their value or US$25 per item, with that rate increasing to US$50 per item after June 1.

Trump had signed an initial order on February 1 ending duty-free entry for the cheap Chinese goods, but later paused the order because of logistical issues complicating the inspection of millions of the low-value shipments.

The number of shipments entering the US through the duty-free route has exploded in recent years, reaching nearly 1.4 billion packages last year.

More than 90 percent of all packages coming into the US now enter via de minimis, and of those, about 60 percent come from China, led by direct-to-consumer retailers such as Temu and Shein.

Trump's order affecting de minimis parcels was paused on February 7 because there had not been sufficient time to prepare, with packages stacking up at ports of entry.

The White House said carriers transporting the mainland Chinese and Hong Kong postal items must "report shipment details to US Customs and Border Protection (CBP), maintain an international carrier bond to ensure duty payment, and remit duties to CBP on a set schedule."

It said CBP may require formal entry for any postal package instead of the specified duties.

The White House said the commerce secretary would submit a report within 90 days assessing the order’s impact and considering whether to extend these rules to packages from Macau. (Reuters)