China's top diplomat has pledged that it would contribute more to global development.

While defending Beijing's policies at a forum here yesterday, Politburo member Yang Jiechi also blasted countries resorting to trade protectionism and a "simplistic, palliative approach" to problems.

"It is peaceful development, not predatory expansion, that has enabled China, a country once mired in poverty and backwardness, to grow into the world's second-largest economy," he said.

"For this reason, we will continue to uphold peaceful development and cooperation for win-win results."

Mr Yang was delivering the keynote address at the opening of the World Peace Forum at Tsinghua University.

Established in 2012 and now into its seventh edition, the high-level forum hosted by the university and co-organised by the Chinese People's Institute of Foreign Affairs provides a platform for politicians, scholars and students from around the world to discuss international peace and security issues.

Noting that China is a key engine of global economic growth - accounting for 10.2 per cent of global imports and 12.8 per cent of global exports last year - Mr Yang said Beijing would work with all parties to uphold free trade as well as the multilateral trading regime and to combat the "unilateralism and protectionism (that) have jeopardised global growth".

China's development "would not have been possible without the outside world so, in return, China will contribute more to global development," he said.

He said this included more comprehensive opening up of its economy, working to ensure sustained progress in its Belt and Road Initiative to build a new Silk Road of infrastructure and trade links, and taking an active part in reforming the global governance system to make it more equitable and just.

He cited the first China International Import Expo, to be held in Shanghai this November, and the second Belt and Road Forum next year as proof that China is committed to global trade and joint cooperation.

Separately, Vice-Foreign Minister Le Yucheng repeated Beijing's rejection of the United States' claims that it forces technology and intellectual property transfers and that the World Trade Organisation (WTO) did not address China's unfair trade practices.

Describing China as a latecomer to global trade, he said that Beijing did not set the rules, and fulfilled all requirements to join the WTO.

"Last year, China's trade in goods alone reached US$4.1 trillion (S$5.6 trillion). This amount is not reached through coercion but mutual benefit and win-win," he said. "Business people are not stupid, they won't willingly swallow 40 years of unprofitable trade."

Mr Le also said that expecting China's pace of opening up to equal that of the developed world was unrealistic.

"That's like asking two boxers of different weight classes to compete on the same stage, or two cars with different horsepower to compete on the same track - which will be most unfair," he said.

Other speakers yesterday also praised China's approach towards globalisation compared with the route the US has taken.

Former European Commission president Jose Manuel Barroso said leaders have an obligation to their people not to present foreigners as the enemy but as possible partners, and to discard the zero-sum mindset to global problems.

"When there are problems like the ones we have seen recently, the solution is not to raise new protectionist barriers, but to ask others to open further, including China," he said. "I really welcome the recent developments in China of opening up more to foreign investments, (and) it is important that China also keeps its momentum of further opening up."