UN chief Ban Ki-moon on Thursday urged the European Union to "play a role as a locomotive" in the upcoming negotiations on climate change to be held in Copenhagen in December.

"I am pushing leaders to act as global leaders and the European Union's role will be critically important. The European Union can play a role as a locomotive," Ban said at a joint press conference with Swedish Prime Minister Fredrik Reinfeldt.

The UN secretary general said he hoped the European Union, under the leadership of Sweden which currently holds the EU presidency, would encourage countries not ready or reluctant to alter their habits to fight climate change.

Ban added that Europe had "the most capacity in terms of finance, in terms of technology, in terms of political will."

The EU has committed to reducing its greenhouse gas emissions by 20 percent from 1990 levels and has said it could increase the target to 30 percent if an international agreement was reached in Copenhagen.

Such an agreement seems however unlikely as the United Nations itself has admitted that international talks on climate change currently taking place in Bangkok are not moving fast enough.

Disagreements have also emerged among EU member states on a proposed carbon tax on imports from regions with poor environmental standards, threatening the bloc's common stance on the matter.

The December 7-18 talks in Copenhagen, under the 192-nation UN Framework Convention on Climate Change (UNFCCC), aim to craft a post-2012 pact for curbing the heat-trapping gases that drive perilous global warming.