"We have to recognise that developing countries can only be expected to engage if economic incentives are put in place," said Yvo de Boer, executive secretary of the United Nations Framework Convention on Climate Change (UNFCC).
Boer said that a few countries such as the United States and Japan have contributed several billion dollars to a climate change fund to help other nations cut their emissions.
"The World Bank is working to establish a number of new financial mechanisms. They have just created a new investment facility which the US has committed three billion (dollars) to...," de Boer said at a news conference.
Japan has pledged 10 billion dollars to the fund.
Developing countries could not be expected to accept mandatory targets on reducing greenhouse gas emissions, the official said.
De Boer is in India to take part in the annual Delhi Sustainable Development Summit which begins Thursday.
India has refused to accept binding cuts on its greenhouse gas emissions, saying it would slow down its economic growth and efforts to lift millions out of poverty.
The official warned that emissions would increase considerably rather than reducing if timely action was not taken.
"Economic realities are telling us that emissions without action will go up by 50 percent (by 2050)," Boer said.
At last year's UN climate change conference, delegates delivered a roadmap which set out the framework for negotiations for a long-term agreement on emissions which will replace the landmark Kyoto Protocol that expires in 2012.