A UN-led panel on climate change is expected to complete a summary of a report detailing ways to combat global warming by a Friday deadline, though major differences between nations are still being hashed out, delegates say.

The report of the Intergovernmental Panel on Climate Change, a United Nations network of 2,000 scientists, is expected to call for quick action in curbing greenhouse gas emissions and reducing energy consumption.

Delegates from over 120 nations have been hammering out the final details of a summary for policy-makers all week at a climate change conference in Bangkok.

And although there have been reports of resistance from countries such as China, India and the United States over the wording and emphasis of the summary, it is expected to be released on time Friday, delegates said.

French delegate Michel Petit said the debate was going more smoothly than anticipated.

"China and India were the governments having more questions and requesting changes in the existing text," he said. "But up to now, every time we were able to overcome their concerns and come to an agreement."

The report is expected to urge nations to adopt a number of reforms, including a shift away from coal as an energy source, investment in energy-efficient technologies, agricultural reform and the adoption of policies — such as emission trading — to encourage a slowing of greenhouse gas production.

Talks were expected to continue into the night over a few contentious issues. China is said to want language in the document urging richer countries to take the lead in reducing emissions. The United States is also fighting for nuclear power to be referred to as a source of clean energy, to the objections of some environmentalists.

'Message is protected'

"We don't believe that nuclear is a solution," said Stephan Singer of the World Wildlife Fund.

Canadian environmental consultant Erik Haites, who was a review editor for a section of the upcoming report, said at this stage politicians can do little to change the substance of the report.

"The structure of the process ensures [the] essential message is protected," Haites told CBC News Online. "The authors of the summary cannot make changes inconsistent with the report, so the basic message does not get lost or distorted."

The summary for policy-makers is a streamlined version of the actual report, which is expected about a month later.

The report is the third of four to be produced by the Intergovernmental Panel on Climate Change this year. The first report laid down the scientific foundations for the next three, stating that global warming was "unequivocal" and very likely caused by man-made greenhouse gases produced from the burning of fossil fuels.

The second report — which so far has only come out as a summary for policy-makers — looked at the consequences of global warming, predicting widespread extinction of species and water shortages in the developing world if temperatures were to rise by even two degrees.

A fourth report, summarizing the finding of the previous three, is expected in the fall.

With files from the Associated Press