BEIJING - China's Executive Vice-Premier Han Zheng has pledged further opening up of the Chinese economy as a trade war with the United States looms, vowing to level the playing field for foreign firms.

Mr Han, who was speaking at the annual China Development Forum on Sunday (March 25), pointed out that as China transitions from high speed to high quality growth, "opening up means prosperity while staying closed leads to decline".

Mr Han said this opening up will involve bringing in foreign investments into China as well as Chinese firms going out to the world.

"China will treat domestic and foreign companies as equals and better protect intellectual property rights and other legitimate rights and interests of foreign companies," he told an audience that included global business leaders.

China's opening up in the past four decades, he noted, "has promoted reform and development and created opportunities for the whole world".

"As we pursue high quality development, we need to open up even wider to the outside world," he added, in his first major remarks since taking office this month.

Foreign companies have complained about unfair treatment compared with local firms.

Mr Pascal Lamy, former director-general of the World Trade Organisation, weighed in on Sunday in his speech at the forum, saying that China's non-tariff barriers made it less of a level playing field for foreign firms.

"The major issue is about conformity assessment, about quality assessment, about norms and standards, and on this I think there is still quite a long way to go to ensure a level playing field between Chinese producers and foreign producers whether they produce outside or within China," he said.

He also pointed to subsidies, particularly in the state-owned sector, that distorted competition.

China's new central bank governor Yi Gang said China would reform and open up its financial sector while Vice-Minister for Commerce Wang Shouwen said China would further open up its finance, telecom, healthcare and education sectors to foreign investors.

A key reform China will implement is letting the market play a decisive role in allocating resources, said Mr Han, adding the role of the government must be minimised.

In his remarks, Mr Han also noted that economic globalisation was an irreversible trend.

And while things would not be smooth sailing, countries resorting to trade protectionism would not solve globalisation's problems.

"Unilateralism or trade war serves the interests of none. It will only lead to serious consequences and negative impact," he said.

Mr Han did not name the US in his remarks but Washington has imposed tariffs on steel and aluminium and announced plans on Thursday to impose more tariffs of up to US$50 billion (S$66 billion) on Chinese products to compensate for what it deems as China's predatory economic practices.

China last Friday announced proposed retaliatory tariffs of about US$3 billion on US imports ranging from fresh fruit and wine to steel pipes and recycled aluminium.

Mr Han on Sunday called for countries to "work together to promote trade and investment liberalisation and facilitation and make economic globalisation more open, inclusive, balanced and beneficial for all".

China, for its part, will continue to "pursue the basic state policy of opening up and break new ground in all-round opening up".