China has urged the United States to stop "politicising trade and economic issues" and vowed to take unspecified "necessary measures" after the United States Postal Service (USPS) announced it had temporarily stopped accepting parcels from mainland China and Hong Kong.

The USPS said the suspension will remain in place until further notice, with the move coming after US President Donald Trump slapped extra tariffs on Chinese imports and ended a duty-free exemption for low value packages.

"The Chinese government calls on the United States to stop politicising and weaponising trade and economic issues, stop going after or suppressing Chinese companies," said Foreign Ministry spokesman Lin Jian at a regular media briefing on Wednesday.

"China will take necessary measures to safeguard the legitimate rights and interests of Chinese companies."

Lin said Beijing "deplores and firmly opposes" the move by Washington regarding Chinese goods.

In response, China announced countermeasures of tariffs on a number of US goods, which will take effect next Monday.

"What [action] China takes is necessary to protect its legitimate rights and interests. Trade wars and tariff wars have no winners. Threatening China with pressure leads nowhere," Lin said.

"China urges the United States to correct its wrongdoings, solve each side's concerns through equal-footed consultation, and promote the sound, stable and sustainable development of China-US relations."

Beijing also called for dialogue between China and the US after Trump said he was in no hurry to speak to President Xi Jinping.

Lin said what is needed is not unilateral, additional tariffs but exchanges based on equality and mutual respect.