A grouping of the world's top greenhouse gas emitters on Sunday backed UN-led efforts to forge a global pact to fight climate change but disagreed on a sectoral approach to curb emissions from industry.

G20 nations ranging from top carbon emitters the United States and China to big developing economies Brazil, Indonesia and South Africa held three days of talks near Tokyo to discuss ways to tackle rapidly rising emissions.

'It's not so much these two groups are at loggerheads with each other, they are also thinking of how they can co-operate collectively,' Halldor Thorgeirsson of the UN Climate Change Secretariat said.

The developing world is demanding rich states do more to curb their own emissions and help poorer countries pay for clean technology. Both sides managed to bridge differences in Bali last December to launch two years of talks on a pact that binds all nations to emissions curbs to replace the Kyoto Protocol.

'The whole debate on climate change is moving away from just being an issue of targets to being an issue of how to reduce emissions,' said Thorgeirsson, who was pleased with the G20 talks that were billed as a dialogue, not a negotiation.

'This is a very good sign that the good spirit of Bali will prevail in Bangkok as well,' he said, referring to the March 31-April 4 meeting in the Thai capital, the first UN-led climate meeting of nations that backed the 'Bali roadmap'.

But some G20 members and delegates voiced concern over Japan's proposal for sectoral caps for polluting industries.

Japan wants top greenhouse gas emitting nations to assign near-term emissions targets for each industrial sector which, added up, would then form a national target.

But it was unclear if this target was mandatory or voluntary and developing nations said the scheme needed to take into account their individual circumstances. 'It is clear that developed and developing countries are still far apart on sectoral approaches,' South African Environment Minister Marthinus van Schalkwyk said.

Ailun Yang of Greenpeace China said developing countries objected to the Japanese idea of abandoning binding targets for rich nations by just setting their own targets based on sectors.

'There was very clear opposition to this. Not just China and Brazil, but also South Africa, not just developing countries, even countries like Germany, Spain and Korea.'

Indonesia called for more funding and the transfer of clean energy technology. Otherwise a sectoral approach would not work.

'The goal is the same for developed and developing countries, but there are big differences in thinking,' said Japanese trade minister Akira Amari. 'It was good that we had frank discussions on what each wanted the other to do,' he added.

The talks in Chiba, near Tokyo, also sparked a row over big developing nations being labelled 'major emitters', a term US officials used at the gathering.-Reuters