Indian Prime Minister Manmohan Singh will attend the end of the UN climate summit, joining dozens of leaders including US President Barack Obama, in the latest sign of growing momentum toward a new global accord.

Singh will go on December 17 to the Copenhagen talks which are due to end the following day, a spokesman in the prime minister's office said on Saturday.

India, the world's fourth biggest emitter of greenhouse gases, said this week that it would aim to cut carbon intensity by 20-25 per cent by 2020 compared with 2005 levels. Carbon intensity is the amount of carbon dioxide emitted for each unit of economic output.

The White House said on Friday that Obama would attend the end of the Copenhagen summit, rather than on December 9 as originally planned, and the US administration has been encouraged by announcements by India and China setting targets to rein in emissions.

India had come under intense pressure to issue targets before the summit after the United States and China announced their plans on reducing emissions, and its modest targets may still fail to impress rich countries as they are "legally non-binding".

But Singh's presence will signal greater seriousness of intent, the environmental group Greenpeace said.

"India and China are key to the talks and Singh being there gives us more credibility, gives our negotiations greater clout and shows more seriousness on our part to reach a decision," said Ankur Ganguly, Greenpeace's communications manager in India.

"It is a display of positive intent and flexibility on India's part, and a sense of solidarity as other leaders will also be there," he added.

Chinese Premier Wen Jiabao will also attend the talks, which open on Monday and aim to lay the foundation for a successor to the 1997 Kyoto Protocol on cutting global warming gases.

Indian Environment Minister Jairam Ramesh, while unveiling the country's negotiating position this week, said India needed to show leadership, and be "flexible without compromising our basic national interest". There was no question of accepting a legally binding emission cut, he added.

Developing countries, which are under no obligation to make any cuts under existing global pacts, say they could make the shift to less polluting economies with help from the rich.

But there are deep rifts between rich and poor nations about how to share the burden of global warming. – Reuters