BANGKOK (Reuters) - Poorer countries are helping shape a broader pact to fight climate change but their efforts are being stymied by rich nations lack of commitment on finance and tougher emissions cuts, the UN said on Thursday. Funding to help poorer nations is a make-or-break issue in negotiations to seal a broader climate pact to replace the Kyoto Protocol at a summit in Copenhagen in December. Poorer nations are demanding cash to help them adapt to the effects of climate change, such as rising seas, and green their economies to slow the rapid rise of their carbon emissions. But there is still no agreement on the size of climate funds or how to manage them. There has to be a quid pro quo, you have to see a significant advance on the finance. Otherwise, whats the point? Yvo de Boer, the head of the U.N. Climate Change Secretariat told reporters on Thursday in the Thai capital. He said developing nations had shown very constructive engagement in designing parts of a new agreement covering steps to curb emissions, adaptation, technology and a U.N. carbon credit scheme that rewards preservation of forests. But rich nations remained a roadblock, he said. Unless we see an advance on ambitious industrialised country targets and significant finance on the table, it is very difficult for negotiators in this process to continue their work in good faith. And that is the stark reality of where we are at the moment. Delegates at marathon climate talks in Bangkok that end on Friday are trying to trim down a complex draft text that will form the basis of a new climate agreement. After Friday, officials from nearly 200 countries have only five formal negotiating days left before the December 7-18 Copenhagen meeting and anxiety is growing that too many critical issues are being left until the last-minute. A 5-day negotiation session is set for Barcelona early next month. Drawing in big developing nations such as China, the worlds top carbon emitter, India, Indonesia and Brazil into a new agreement is critical if the world is to avoid the worst impacts of climate change, the UN says. Total emissions from poorer nations now exceed those from rich countries. I think a number the developing countries feel that they have been putting a lot of initiatives on the table, Alden Meyer of the Union of Concerned Scientists told Reuters. Brazil has pledged an 80 percent reduction in deforestation by 2020, Indonesia has said it would craft a policy to cut emissions by 26 percent by 2020 from business as usual levels and China has said its carbon intensity-the amount of carbon emitted per unit of energy consumed-would come down by a notable margin by 2020 from 2005 levels. They dont see the Northern side putting much on the table, Meyer said.If people dont start showing their cards theres not going to be a card game in Copenhagen. Its like were kicking over the table because no one wants to play the game, he added. Rich nations say they are willing to offer financing and other measures but that poorer countries must formally put their pledges to curb emissions on the negotiating table and add them to a binding international climate treaty.