China has great expectations for the ongoing climate talks in Copenhagen, and has called on all parties concerned to exert more efforts to ensure the success of the conference.

Xie Zhenhua, head of the Chinese delegation to the UN-led climate conference, said Monday that progress has been made at the climate talks but negotiators were still engaged in heated debates over some key issues.

Xie, who is also vice minister of the National Development and Reform Commission, told reporters that at the start of the talks, the debates focused on what draft texts should serve as the basis for discussion after some unofficial texts of the draft was leaked.

In the end, the dual-track principle for talks under the Bali Road Map was upheld with the emergence of two draft texts proposed by the chairs of two major working groups of the UN Climate Change Conference, Xie said.

The two texts meet the requirements of the Bali Road Map in format, but "we are not fully satisfied with the texts," he said.

Many of the issues in the texts need further discussion and modification, and the ensuing substantial discussion on the texts would be very hard, given the differing national interests and different understandings of the Kyoto Protocol, he noted.

Many sticking points had not been resolved yet, such as the binding targets of emissions reductions for the United States, which is not a party to the Kyoto Protocol, he said.

Ministers arrived in Copenhagen over the weekend to work for consensus on the texts at a higher level of the two-week talks. More than 100 heads of state or government are expected to be arriving later in the week for a climate summit to endorse efforts to fight global warming.

Chinese Vice Foreign Minister He Yafei said here on Sunday that China has great expectations for the Copenhagen climate talks, which must be a success in order to take measures to avoid calamitous global warming.

"Climate change is a challenge the whole global community faces, failure in the Copenhagen climate conference is not an option," He told Xinhua in an interview.

"As a big country, China will do its share, so we've taken a constructive and positive approach at the Copenhagen talks and elsewhere," he said.

Last month, China announced that it would reduce the intensity of carbon emissions per unit of its GDP in 2020 by 40-45 percent from 2005 levels. Later this week, Chinese Premier Wen Jiabao will join more than 100 heads of state or government in Copenhagen for a climate summit.

"China's efforts are unconditional and not tied to emission cuts by other countries. China has made remarkable contributions to the global fight against climate change," he said, adding: "China will continue to work with other countries to push for a successful outcome of the Copenhagen conference."

"It's time for developed nations to show their political will and turn their political will into substantial emission reductions targets," the Chinese official said.

During a telephone conversation on Sunday with South African President Jacob Zuma, Chinese Premier Wen Jiabao exchanged views on ways to tackle climate change.

The two leaders agreed that as the ongoing climate talks in Copenhagen have entered a "crucial stage," all parties concerned should lose no time in consulting with one another and striving for consensus to ensure that the climate talks move along the right track to achieve just, reasonable and realizable results.

Meanwhile, a senior Chinese official said efforts should be made simultaneously in the fields of politics, economy, society, culture and ecology in order to deal with climate change.

"Only through this comprehensive approach can a systematic framework be set up against climate change," said Zhao Baige, vice minister of China's National Population and Family Planning Commission.