Addressing 37 leaders from Europe, Africa, Asia and Latin America, Xi made a new pitch for his cherished Belt and Road Initiative (BRI) as he kicked off the last day of a three-day forum.

The world's number two economy has been fighting a festering trade war with the United States for months, and Xi has long sought to take the mantle of the new world power open to multilateral cooperation and globalisation.

"We need to build an open world economy and reject protectionism," Xi told leaders including Russian President Vladimir Putin, Italian Prime Minister Giuseppe Conte and Pakistan's Imran Khan seated around a large round table at the idyllic Yanqi Lake retreat at the edge of Beijing.

A draft communique for the forum seen by AFP similarly pledges to "reject protectionism" and "unilateralism" in an oblique swipe at President Donald Trump's "America first" presidency. US officials were not sent to the summit.

Xi's signature foreign policy aims to reinvent the ancient Silk Road to connect Asia to Europe and Africa through massive investments in maritime, road and rail projects -- with hundreds of billions of dollars in financing from Chinese banks.

"We need to encourage the full participation of more countries and companies, thus expanding the pie of common interests," Xi said.

But critics say BRI is a plan to boost Beijing's global influence, riddled with opaque deals favouring Chinese companies and saddling nations with debt and environmental damage.

The United States, India and some European nations have looked at the project with suspicion.

Rising resistance

So far Chinese companies and workers have emerged as the primary beneficiaries as they are tapped to build the China-financed infrastructure in other developing countries.

BRI projects have faced pushback in some countries. In Malaysia, Prime Minister Mahathir Mohamad cancelled some planned works and renegotiated a rail project cutting 30 percent off the price tag.

But Mohamad and other leaders attending the summit had fulsome praise for BRI.

The draft communique says BRI will welcome developed countries and international investors to participate in the projects.

Xi batted away some concerns at the opening ceremony Friday, saying the BRI will have "zero tolerance" for corruption while vowing to ensure the financial sustainability of projects and further open China's economy.

"Faced with this rising resistance for the past year and a half and this debt image ... China is trying to reposition (BRI) and send a reassuring message," said Nadege Rolland, a senior fellow at the National Bureau of Asian Research, a US-based think tank.

But "let's see how it is put into practice," she said.

China's finance ministry released guidelines Thursday for assessing financial risk and debt sustainability to apply to projects in BRI countries.

But the document notes that countries already facing payment problems or in the process of restructuring payments "does not automatically mean that debt is unsustainable in a forward-looking sense."

During a state banquet Friday night, Xi called on attending world leaders to band together in the face of setbacks.

"Certainly, while building the Belt and Road Initiative, we will face difficulties and there will be twists and turns," he said.

"No matter a smooth or challenging way, we need to continue the spirit of partnership, not forget our initial intention of cooperation and move forward unwaveringly," he said.