At the last round of negotiations in Cancun in 2010, all sides agreed on $30 billion in fast-start funding to help poorer countries adapt to the impact of rising temperatures and changing weather patterns up to 2012, with plans to increase the amount to $100 billion a year by 2020.
Xie said the $30 billion commitment is now unlikely to be met, but expressed hope that mechanisms for a green climate fund could still be established at Durban.
"We understand the difficulties facing Western countries, but the problem we are talking about now is a long-term financing mechanism while the economic problems are temporary."
With little progress expected at Durban, environmental groups have said time is quickly running out if the world is to stay below a 2 degrees Celsius temperature rise.
The World Meteorological Organization said on Monday that carbon dioxide levels rose to 389 parts per million last year, an annual rise of 2.3 ppm and edging closer to the 450 ppm level that could precipitate two degrees of warming.
It said concentrations of the three main greenhouse gases blamed for global warming reached record levels in 2010.
Xie reiterated China's support for an extension to the Kyoto Protocol beyond its first "commitment period" ending in 2012, despite opposition from a number of developed countries. Kyoto sets emissions caps on about 40 rich nations.
"How to solve this problem is actually a very central, very key problem at the Durban meeting," said Xie.
Beijing has been one of the big winners of the Kyoto Protocol's Clean Development Mechanism, which allows industrialized countries to earn carbon credits by investing in clean projects in developing nations.
China has by far the largest number of CDM projects and its success has prompted Europe, the biggest carbon credit market, to seek changes to the CDM and the Kyoto Protocol beyond 2012, saying it currently lacks environmental integrity.