The world's major greenhouse gas emitters headed into a final session of talks on Sunday on the shape of a post-Kyoto Protocol climate pact, with Japan's aim to promote sectoral caps for industry under fire.

Japan is hosting a three-day meeting of G20 energy and environment ministers and feels capping emissions for polluting industries such as power generation is one way to curb rising carbon dioxide emissions.

But developing nations in the grouping feel the concept is unclear and want more specifics, something the Japanese haven't provided in great detail, delegates say.

Japan is also resisting using 1990 as the base year for emissions cuts for a new global pact to replace the Kyoto Protocol.

"We need to see the analysis behind all of this," said one delegate, adding Japan's industry ministry appeared unwilling to take into account poorer countries' concerns about sectoral approaches.

"People are willing to listen and understand what the issues are. But you can't come and try and shove your position down somebody's throat without being sensitive to their own national circumstances," the delegate said.

They said poor nations wanted talks on how the concept would apply to steelmakers and aluminium smelters, for example.

"The sectoral approach is not good in the sense that we already have our own national development and climate change strategies," said Indian delegate Prashant Pise.

"The sectoral approach is basically a concept promoted by a few sectors or industries," he added.

Britain has rejected the concept as vague and said binding national targets were the only way forward for all nations in the fight against greenhouse gas emissions blamed for rising seas, melting glaciers and more extreme droughts and storms.

G20 members, which include G8 nations, plus big developing nations such as China, India, Brazil and Indonesia, are responsible for about 80 percent of mankind's greenhouse gas emissions.

DIFFERENCES

About 190 nations agreed at U.N.-led talks in Bali last December to launch two-year negotiations on a replacement for Kyoto, which binds only rich nations to emissions cuts by an average of five percent between 2008-2012 from 1990 levels.

All nations would be bound under Kyoto's successor from 2013 and under the "Bali roadmap", nations recognised deep cuts in global emissions were needed.

But there are wide differences over the size of binding targets, the base year for those targets as well as management and funding of schemes to provide clean energy technology to poor nations.

Europe has pledged to cut greenhouse gas emissions by 20 percent by 2020 from 1990 levels.

But while Japan has backed a 50 percent reduction by 2050, it has rejected the 1990 base year, saying it was unfair to their industry, which had already made energy efficiency investments in two decades ago. Japan prefers a 2020 base year.

"There is no consensus on what the base year for emission levels is. Some countries are saying 1990, like the European Union but there are many countries that haven't decided on the base year," said Pise.

"India's stance is that we want to do whatever we can but at the same time, there is responsibility for industrialised countries."