Online shopping giants Temu and Shein have seen a sustained drop in sales in the week after US President Donald Trump scrapped a duty exemption that their small parcels benefit from, suggesting a chilling effect on American consumers who previously flocked to their ultra-cheap wares.

Sellers and shoppers on the two sites say they saw items disappear and prices go up after President Donald Trump implemented tariffs on Chinese imports.

A decision by President Trump to close a tariff loophole could change the landscape of online shopping, particularly for the Chinese e-commerce companies behind wildly successful sites, such as Shein and Temu.

Online shopping giants Temu and Shein have experienced a sustained decline in US sales following President Donald Trump’s announcement to revoke the duty-free exemption on small parcels under $800 from China.

Shein and Temu shifted more of their orders to be fulfilled in the US ahead of de minimis changes.

The era of "fast fashion" might be over. President Donald Trump's new tariffs on China will make purchases from Shein and Temu more expensive, and that's if the shipments can even get into the United States.

Shein’s US sales fell 16 per cent to 41 per cent for five days from February 5 while Temu’s fell as much as 32 per cent.