EU environment ministers clashed over a huge surplus of UN pollution permits, a technical spat with the potential to derail international efforts to tackle climate change.

Settling the issue is crucial to UN environment talks in Doha, beginning next month, which will seek to hammer out the detail of a second phase of climate action after the first Kyoto commitment period expires at the end of this year.

"There is no agreement in sight," an EU official said on Thursday, speaking on condition of anonymity. "We have not moved at all from last year. The lack of agreement could endanger a second commitment period. We have to get a deal."

The Kyoto process is the only international framework for tackling climate change and the European Union has played a leading role in it.

Many EU nations have said the European Union's environmental integrity would be undermined if it held on to an excess of allowances - officially named Assigned Amount Units (AAUs) and referred to disparagingly as "hot air".

But coal-dependent Poland has repeatedly opposed efforts to stop it keeping its hoard of AAUs and on Thursday it had garnered the support of other eastern European and Baltic states.

EU officials referred to "an east-west divide".

'Acquired right'

Polish Environment Minister Marcin Korolec told reporters the so-called hot air, was "an acquired right" and said the talks, meant to have been over by early evening, could drag on through the night.

Poland has met its emissions-cutting goals, he said, leaving it with permits to spare, which can be sold to nations who have exceeded their pollution limits.

On the opposite side of the debate, nations, such as Britain, Denmark, France and Germany, have argued the excess permits need to be cancelled, not only to ensure EU integrity and climate ambition, but to create a level playing field for all nations, including developing countries.

Emerging economies were not part of the first Kyoto commitment period and therefore have no surplus permits to retain or sell on.

Agreement on AAUs proved impossible a year ago when, as then EU president, Poland was at the head of the EU delegation to the Durban international conference on climate change.

Last year's Durban deal managed to keep the Kyoto process alive, but was heavily criticised for its lack of detail. Debate beginning in Doha on November 26 will attempt to plug major gaps, such as fixing the length of a second commitment period.

EU leadership was crucial to achieving any kind of accord in Durban last year, when its negotiating hand was strengthened by an alliance with small nations, including islands, which are sinking as ice caps melt and sea levels rise.

In addition to the problem with AAUs, non-governmental organisations have warned that alliance could be undermined by the reluctance of the world's richer nations to agree on new sources of financing to help poor countries cope with the challenge of climate change.

The European Union has committed cash for the period 2010-12, but has repeatedly failed to come up with any figures beyond then.

Thursday's EU environment ministers' meeting in Luxembourg was only expected to agree vague wording on financing, leaving it for EU finance ministers meeting on November 13 to make any more precise commitments.

Reuters