US President Donald Trump has warned China not to retaliate against a hike in tariffs he imposed last week and says US consumers would not pay for any increase in duties.

There "is no reason for the US Consumer to pay the Tariffs, which take effect on China today ... China should not retaliate-will only get worse!" Trump tweeted, adding that tariffs can be avoided if manufacturers shift production from China to other countries.

"I say openly to President Xi & all of my many friends in China that China will be hurt very badly if you don't make a deal because companies will be forced to leave China for other countries. Too expensive to buy in China. You had a great deal, almost completed, & you backed out!" Trump continued.