Durban: China's top climate negotiator Xie Zhenhua laid out conditions under which Beijing would accept a legally-binding climate deal that would go into force after 2020, when current voluntary pledges run out.
The conditions included a renewal of carbon-cutting pledges by rich nations under the Kyoto Protocol, along with hundreds of billions of dollars in short- and long-term climate financing for poorer countries.
"I think after 2020 we should also negotiate a legally- binding document," Xie told a group of NGOs at talks in Durban under the UN Framework Convention on Climate Change (UNFCCC).
"The problem now is that we have to see whether we have conscientiously implemented the legal documents we already have agreement on. This is a very important issue for us," he said through an official Chinese translator.
The 194-nation talks, which wrap up on Friday, are abuzz with speculation on the prospect of a "Durban accord".     Such a deal could set a pathway for a binding climate pact that would include not just rich countries, as does the Kyoto Protocol, but all major greenhouse emitters, including China, India and Brazil.
Major emerging economies and other developing nations already emit more than half of current carbon emissions, and within 20 years are projected to account for two-thirds.
The European Union launched the idea, tying its support of the Protocol, which risks becoming an empty shell in 2012 without new carbon cutting pledges from industrialized nations, to a "mandate" for a broader 2015 climate pact.
The United States has reacted coolly to the proposal, as has India while host country South Africa, and perhaps Brazil, have expressed a greater openness.
After first saying the EU bid was "too much," China has in the last few days hinted for the first time that it might be willing to take on legal obligations under a new international framework.
Until now, it has insisted that as a "developing" country it was exempt from such obligations.