Countries ready for serious negotiation in Bali: UN

De Boer said that Australia and the United States -- neither of which have ratified the Kyoto Protocol -- "both indicated that they were willing to take on commitments under a future climate change regime" during this week's meet.

But he said long discussions will have to happen well beyond the Bali summit "in terms of what 'commitments' actually means -- what countries will do and whether that will be internationally legally binding or not."

Australia and the United States have said they will press for a new regime that provides for "effective action from all the major emitting nations."

They rejected Kyoto on the grounds that it did not commit developing countries to the same sort of emissions cuts as industrialised nations.

More than 100 ministers are expected to attend the Bali summit