China re-emphasized on Saturday that the principle of "common but differentiated responsibilities" must be reaffirmed in the action plan of the upcoming UN Conference on Sustainable Development (Rio+20), as some developed countries want to delete the term.

Assistant Foreign Minister Ma Zhaoxu told reporters in Rio de Janeiro that the principle insisted by the Group 77 and China is a guideline for international cooperation on sustainable development.

"Practices have proven that the principle is a precondition for international cooperation on sustainable development. All participants should adhere to the principle and it should be fully reflected in the conference outcome," Ma said.

Disagreements over critical issues such as principles to guide the sustainable development goals and green economy remain after the three-day final preparatory committee meeting that ended on Friday evening.

Brazil has accepted the responsibility of getting the draft ready through informal consultations from Saturday in time for world leaders to consider when they arrive.

Premier Wen Jiabao will head to the conference this week and also visit Brazil, Chile, Uruguay and Argentina, according to the Ministry of Foreign Affairs.

Apart from the principle, Ma stated China's major stance on the upcoming global summit on sustainable development, which begins on Wednesday.

Nations should support each other to make concerted efforts to integrate the three pillars of sustainable development, which consists of economic development, social progress and environmental protection.

Developing a green economy is a complex and long-term process, Ma said. It's also extremely difficult for developing countries, so the international community should provide a favorable external environment for developing countries and address their major concerns, he said.

The institutional framework for sustainable development should be further strengthened by giving a bigger say and decision-making power to developing countries and solving their practical difficulties concerning capital, technology and capacity building, as well as strengthening the pillar role of the UN.

"The conference should adopt an action-oriented tangible attitude and lay out specific implementation plans, supplying necessary funding and technologies for developing countries, reducing their debts and helping them boost capacity building," Ma said.

He also urged the conference to specify the principles to guide the sustainable development goal and said it should be complementary to the millennium development goal and the international community should firmly implement the MDG.

Du Ying, vice-minister of the National Development and Reform Commission, who is also head of the preparatory committee of the Chinese delegation, said China is a firm follower and active practitioner of sustainable development.

"But the country still is a developing country, with its per capita gross domestic product only accounting for about 53.4 percent of world average level, and there are still 122 million people living in poverty," Du said at the first event hosted by the Chinese government before the opening of the high-level segment of the conference.

Negotiations on the wording of the draft are still under way and things were better than two days ago, said Nikhil Seth, head of the Rio+20 Secretariat.

"There is no more time left for detailed, word-by-word negotiations. Now we need to get to another mode of negotiations. It's not line by line, but you come to the heart of these major blockages," he said.

The Brazilian government released a streamlined version of the draft on Saturday evening. Lasse Gustavsson, head of delegation of the World Wildlife Fund, a nongovernmental organization, said there is no "political miracle in sight".

The revision is peppered throughout with weak words and is very short on strong language, he said. "Diplomats now only have a few days to salvage this process before world leaders show up," he said.