UN climate talks in Copenhagen in December are unlikely to produce a new global Treaty on cutting emissions but should establish the political framework, the top UN climate official said yesterday.

Yvo de Boer told the Financial Times newspaper that world leaders did not have enough time to agree a legally-binding treaty ahead of the crunch summit.

"A fully fledged new international treaty under the convention - I do not think that is going to happen," said Mr De Boer, referring to the UN Framework Convention on Climate Change .

"If you look at the limited amount of time remaining to Copenhagen, that's clear."

The high-stakes summit in the Danish capital from December 7 to 18 will see nations attempt to hammer out a new global climate treaty to replace the Kyoto Protocol which expires in 2012.

Mr De Boer told the newspaper: "We have to focus on what can realistically be done and how that can realistically be framed."

That meant reaching an "overarching decision at Copenhagen that sets out individual targets for industrialised countries, that decides how major developing countries intended to engage (in curbing emissions by) 2020, and hopefully that puts that in the context of a long-term goal", he said.

World powers should also set a deadline by which time these pledges could be negotiated to a treaty, he said.