RIO DE JANEIRO - China has made great progress on sustainable development despite difficulties along its development path, a senior UN official said here Friday.

As a developing country, China has gone through a more difficult development course than developed countries, said Sha Zukang, UN under-secretary-general for economic and social affairs, at an event on the sidelines of the United Nations Conference on Sustainable Development (Rio+20 Earth Summit).

Looking ahead, China will face many difficulties and obstacles. At present, China has more than 100 million people living below the poverty line, and China still has to work hard in emission reduction and environmental protection, he said.

"But I have full confidence in the road of China's sustainable development. I believe that China has broad prospects in its participation in international cooperation on this subject, especially in technology transfer and capacity building," he said.

He said China's success was attributed to the government's determination and insistence in reform and opening up, focus on people's livelihood, and strategic initiatives to develop a green economy in the framework of sustainable development and poverty reduction.

The Rio+20 summit will take place in Rio de Janeiro, Brazil, from June 20 to 22, and is meant to define pathways to a safer, more equitable, cleaner, greener and more prosperous world for all.

Twenty years after the 1992 Earth Summit in Rio, the United Nations is again bringing together governments, international institutions and major groups to discuss a range of smart measures that can reduce poverty and promote decent jobs, clean energy and more sustainable and fair use of resources.