The final text for a deal on climate change should be presented later this morning, after 11th-hour talks slipped past their official deadline.
Ministers from more than 190 countries have been working through the night in Paris on negotiations to secure a new international climate change agreement.
Countries have been engaged in "shuttle diplomacy" between groups to find common ground.
One negotiator said they are "pretty much there" on an agreement.
Egyptian environment minister Khaled Fahmy, the chairman of a bloc of African countries, told the Associated Press late on Friday: "We are pretty much there.
"There have been tremendous developments in the last hours. We are very close."
Despite a pledge from French Foreign Minister Laurent Fabius that a draft text would be presented at 9am the final draft is now due out at 11.30am (10.30 GMT), according to a French official.
Delegations will then have a few hours to go through the deal - of which no details have yet been released.
The final agreement could include references to making efforts to keep temperature rises to no more than 1.5C above pre-industrial levels - a key ask of the most vulnerable countries who fear greater warming could threaten their very survival - as many countries are thought to be "comfortable" with the idea.
But the level of ambition in the final deal remains one of the key issues, according Mr Fabius, who is chairing the talks.
The issue of "loss and damage" - the recognition that some of the most vulnerable countries need support to cope with irreversible impacts such as inundation of their land from rising sea levels - is also hugely difficult, with developed countries refusing anything that could open them up to liability or compensation.
Finance for poor countries to deal with climate change and the different responsibilities of developed and developing countries to tackle climate change and pay for it, are also still the focus of political dispute.
As the talks headed past the deadline, tensions began to show with Indian environment minister Prakash Javadekar accusing developed countries of not showing flexibility towards poorer countries.
And Marshall Islands foreign minister Tony de Brum, the driving force behind the "high ambition coalition" of countries including the EU calling for a strong deal at the talks, warned there had been a "co-ordinated campaign to gut the text" of ambition by some countries.
The coalition is calling for a robust five-yearly review system which would see countries review and increase their pledged emissions cuts, a move that is necessary as current climate action plans would only limit temperature rises to 2.7C.