Talks are back on track at the UN climate summit after developing countries won significant concessions.

Informal talks will proceed along the two "parallel tracks" favoured by developing countries, in particular on maintaining the Kyoto Protocol.

But the final high-level session starts on Tuesday evening, and much remains to be done if a deal is to be signed here.

Delegates are poring over the details of a new draft text which was released on Tuesday at the summit, the BBC reported.

Non-governmental organisations are protesting that many campaigners will be turned away from the venue.

Far more people have applied to attend the summit than Copenhagen's Bella Center can hold, and NGO numbers will be progressively reduced during the rest of the week, partly for security reasons as heads of state and government arrive.