Premier Li Qiang said on Wednesday trade restrictions have created barriers to doing business and that China would work to reform the global economic and trading system and make trade rules fairer, more reasonable and transparent.

In a keynote speech at the opening ceremony of the eighth China International Import Expo (CIIE) in Shanghai, Li also said Beijing will further open up domestic markets and slammed "unilateral and protectionist" behaviour by other countries.

"Looking at certain unilateral and protectionist actions in the international arena today, we see they severely disrupt the international economic and trade order," he said.

The premier said the international order had been threatened this year by "various forms of decoupling and supply chain disruption, coupled with escalating trade frictions".

He added that many multinational corporations feel it's becoming increasingly difficult to do business, and that developing nations were especially vulnerable to economic turbulence.

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

The premier also said the mainland economy will exceed 170 trillion yuan by 2030, presenting a big market opportunity for the world and contributing to global economic growth.

More than 155 countries, regions and organisations plan to participate in the CIIE, the Commerce Ministry said.

More than 4,100 overseas enterprises are taking part, with US companies maintaining the largest exhibition area for the seventh consecutive year.

The expo runs till November 10. (Agencies)