Chinese President Xi Jinping has urged fellow Group of 20 members to uphold their pledge of not rolling out new trade-restrictive measures, as he opened the two-day summit in Hangzhou.
Global economies should instead work together to boost trade and strengthen the coordination of investment policies, he said yesterday.
A day earlier, leaders of world economic bodies warned of the risk to trade from protectionist measures.
International Monetary Fund managing director Christine Lagarde told a panel session that there is now "an undercurrent of anti-trade movement" at both the political and public opinion levels, which will ultimately lead to declining economic activity.
The Organisation for Economic Cooperation and Development's secretary-general Angel Gurria noted that since the 2008 financial crisis, about 1,400 protectionist measures had been passed.
Yesterday, Mr Xi reiterated the calls he made at last Saturday's Business 20 summit for stronger coordination of macro-economic policies to support long-term growth and maintain financial stability.
TIME FOR ACTION
We should turn the G-20 group into an action team, instead of a talk shop.
CHINESE PRESIDENT XI JINPING
Urging world leaders to match words with action, Mr Xi said: "We should turn the G-20 group into an action team, instead of a talk shop."
China's top leader said the world economy is today at a key juncture, and increasing partnerships among G-20 members is especially important. Economic growth is facing sluggish demand, financial market volatility, and weakening trade and investments.
A new round of technological and industrial revolution has not gained momentum, and major markets are facing the added pressures of an ageing society and a decline in population growth, Mr Xi said.
But if the world powers work together as partners, such challenges can be overcome, he added.
Responding to growing anti- trade sentiments, China, which is hosting the annual summit for the first time, held a meeting of G-20 trade ministers in July, during which members pledged to boost sluggish global trade, and reiterated an earlier pledge not to add new protective measures until 2018.
China also established a trade and investment working group to strengthen trade and investment cooperation among G-20 members.
At the summit's first session yesterday, world leaders discussed ways to strengthen policy coordination and forge new growth drivers.
German Chancellor Angela Merkel said G-20 leaders agreed that they needed to work together to increase world economic growth, Reuters news agency reported.
She added that the group plans to set up a task force on innovation.
Germany will take over the G-20 presidency next year.
In the evening, Mr Xi hosted guests, including Prime Minister Lee Hsien Loong, to a welcome dinner and a tour of the West Lake.
Singapore is not a G-20 member, but is among eight guest nations invited to participate in the summit by Mr Xi.
Global leaders and guests watched a cultural performance, Symphony On West Lake, led by Chinese director Zhang Yimou.
Actors appeared to be dancing on the water, but were actually performing on a platform just below the surface. The 45-minute segment featured a combination of Western and Chinese art, such as the ballet Swan Lake, and traditional Chinese music.