The Asian export giant has courted alternative trade partners throughout months of blistering tit-for-tat tariffs between China and the United States.

"Looking at certain unilateral and protectionist actions in the international arena today, we see they severely disrupt the international economic and trade order," Premier Li Qiang said at the opening of a major import expo in Shanghai on Wednesday.

Li warned, without explicitly mentioning the United States, that the international order had been threatened this year by "various forms of decoupling and supply chain disruption, coupled with escalating trade frictions".

He said "many multinational corporations feel that doing business is now increasingly difficult", and that developing nations were especially vulnerable to economic turbulence.

Li was speaking at the massive annual China International Import Expo, an event touted by Beijing as a platform for international economic cooperation, though foreign business groups have complained in past years the deals it generates lack substance.

Days earlier, US President Donald Trump and Chinese leader Xi Jinping sealed a trade war pause at a meeting in South Korea, tentatively concluding months of friction between the economic and technological powerhouses.

Li on Wednesday said China was ready to work with other countries to "safeguard the stability and smooth operation of global industrial and supply chains".