DURBAN, South Africa - China will agree to participate in a legally binding treaty on climate change after 2020 under certain conditions, a senior Chinese official said on Monday.

China is still a developing country, and other countries should respect a founding principle of the existing agreements that recognizes wealthy nations must do more since they are responsible for most of the greenhouse gas emissions that are causing climate change, said Xie Zhenhua, vice-chairman of the National Development and Reform Commission of China.

"I think after 2020, we should also negotiate a legally binding document. China has really expressed its stance on many negotiating occasions and as I said just now, very clearly, we accept a legally binding arrangement, with conditions," said Xie, who led a Chinese delegation to the UN Climate Change Conference in Durban, South Africa.

The conditions include: new carbon-cutting pledges by rich nations in the second commitment period under the Kyoto Protocol; fast launch of the Green Climate Fund agreed on in Cancun under a supervisory regime; implementing the consensus of adaptation; technology transfer, transparency, capability building and other points agreed upon in the former conferences as well as appraising developed countries' commitment during the first period of the Kyoto Protocol.

"China is willing to bear the obligations of a legally binding commitment matched with China's economic development and capabilities based on the principal of common but differentiated responsibilities, fair and environmental integrity," Xie said.

He insisted that all parties obey the Bali Roadmap and other existing legal frameworks to cut greenhouse gas emissions in a multilateral mechanism.

Maite Nkoana-Mashabane, South Africa's foreign minister who is chairing the conference, said she was "pleased" with China's positive attitude.

China is starting to answer the question of "how do we sign up for the second commitment" in Durban, Nkoana-Mashabane said.

"I am sure other negotiators will be laying their cards on the table," she told reporters Monday, adding that would really get things moving, hopefully in the right direction.

The 17th Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC) is taking place in Durban, South Africa, from November 28 to December 9, to review and discuss global climate change challenges and look for global commitments to curb greenhouse gas emissions.