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.
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.
UK Prime Minister Gordon Brown will be one of the first leaders here, arriving on Tuesday evening.
Protocol matters
Following Monday's suspension of talks on points raised by the African group, supported by the wider G77-China bloc of developing countries, some sessions ran long into the night as negotiators tried to make up lost time.
The Danish conference hosts had been accused of trying to sideline negotiations on the Kyoto Protocol by packaging discussion of outstanding difficult issues from across the various strands into a single informal session.
Developing countries are adamant that developed nations still inside the protocol - all except the US - must commit to further emission cuts under its aegis.
After discussions with the Danes and UN climate convention officials, the informal talks were split as the G77-China bloc had demanded.
One group, chaired by Germany and Indonesia, is examining further emission cuts by developed nations under the Kyoto Protocol.
Another, chaired by the UK and Ghana, is looking at long-term financing to help poorer countries develop along "green" lines and protect themselves against impacts of climate change.
A senior Chinese source, meanwhile, confirmed to BBC News that China would not accept any money from the west for these purposes.
This is likely to carry political significance in the US, where some legislators are adamant that domestic carbon-cutting measures must not hand funds to the country set to emerge as its biggest economic rival.
Here, the positions of the world's two largest emitters are very much at odds, with China rejecting US demands that its emission curbs must be subject to international verification.
'Losing legitimacy'
After the chaos over access to the Bella Center on Monday, when thousands of people already registered to attend queued for hours in a vain attempt to pick up their accreditation, progressively tighter restrictions are being applied to NGOs for the rest of the week.
THE WEEK AHEAD
Tues 15 Dec - Prince Charles delivers a speech on the sustainability of human society; UK Prime Minister Gordon Brown arrives
Weds 16 Dec - High-level segment begins; protests expected inside and outside centre
Fri 18 Dec - More than 100 world leaders, including Barack Obama, attend closing session
Numbers will be limited to 7,000 on Tuesday and Wednesday, falling to 1,000 on Thursday and just 90 on Friday.
A group of more than 50 organisations including ActionAid, Friends of the Earth and CAFOD has written to the Danish hosts and the UN climate convention secretariat accusing them of "undemocratic" behaviour.
"The presence of the public ensures that the substance of the matters being discussed at the negotiations are subject to public scrutiny," the letter says.
"The process of arriving at these outcomes must be fair, open and transparent. The legitimacy of this process is at stake."
An unprecedented number of people - 45,000 - have registered to join the conference, about half of them from NGOs. The centre's capacity is only 15,000.
Head space
The final high-level segment of the summit, due to be attended by about 120 heads of state and government, will open on Tuesday evening with speeches from dignitaries including UN Secretary-General Ban Ki-moon, Danish Prime Minister Lars Lokke Rasmussen and Prince Charles.
Speaking to reporters before flying out from New York, Mr Ban warned that "time is running out".
"If everything is left to leaders to resolve at the last minute, we risk having a weak deal or no deal at all," he said.
"And this would be a failure of potentially catastrophic consequence."
Prince Charles's speech will look at climate change in the context of wider concerns about the sustainability of human society.
He is expected to argue that although the human race has created the modern problem of climate change, the human race also has the capacity to solve it.
China has accused developed countries of backtracking on what it says are their obligations to fight climate change and has warned that the UN climate talks in Copenhagen have entered a critical stage.
Foreign Ministry spokeswoman Jiang Yu said there had been "some regression" on the part of developed countries, who had "put forward a plethora" of demands on developing countries.
Beijing's view is that the US and other richer nations have a historical responsibility to cut emissions, and any climate deal should take into account a country's development level.
