A proposed Green Climate Fund to mitigate climate change effects on poor nations and further low carbon development was agreed at the Cancún summit in December 2010.
Indeed, one of the few firm deadlines to emerge from that meeting was for a "transitional committee" to start designing the fund on 14 March.
But groups of Asian, Latin American and Caribbean countries have still not decided who will attend the 40-nation UN talks in Mexico City.
John Ashe of Antigua and Barbuda, who represents the Latin American and Caribbean group in which 14 countries are vying for seven seats on the fund planning committee, doubted that the matter could be resolved by the middle of the month.
"Proceeding with the meeting would be a tall order" without all the nominees in place, he said. The Asian group has announced that it will be unable to pick its seven delegates before April.
"It may be difficult to have the meeting," Artur-Runge Metzger, the head of the European Union delegation confirmed.
Europe's eight delegates have at least been decided. But competition for the remaining seats at the committee table has been fierce, and the stakes are high.
OPEC nations in the Asian group, for instance, are demanding compensation for a loss of oil revenue if the world shifts to wind or solar energy
The so-called BASIC countries – Brazil, South Africa, India, and China – on 27 February criticised the organisation of the talks for not taking guidance from the main UN climate forum, which will not meet until 3 April in Bangkok.
"The decision to convene a meeting of the transitional committee, even before many regional groups of countries have nominated their members, was premature," read a joint statement issued after talks in New Delhi.
Runge-Metzger said the statement made the March meeting less likely, although the talks could still be downgraded to an informal session, open to all countries.
For Ashe, a delay was not necessarily a setback. "If a meeting is not held in March, additional meetings could be held in coming months," he said.
The head of the UN Climate Change Secretariat, Christiana Figueres, said in Japan on Tuesday that "governments must now implement quickly what they agreed in Cancún".
The Secretariat has published a 'progress tracker' for Cancún: the list of transitional committee members is blank.
(EurActiv with Reuters.)