Diplomats from 192 nations were present in the Copenhagen summit.
Conference president Connie Hedegaard said, "The key to an agreement is finding a way to raise and channel public and private financing to poor countries for years to come to help them fight the effects of climate change."
Hedegaard, Denmark's former climate minister said, "If governments miss their chance at the Copenhagen summit, a better opportunity may never come."
"This is our chance. If we miss it, it could take years before we got a new and better one. If ever," she said in prepared remarks.
Denmark's Prime Minister said 110 heads of state and government will attend the final days of the two-week conference.
The first week of the conference will be focused on refining a complex text of a draft treaty.
But major decisions will await the arrival next week of environment ministers and the heads of state in the final days of the conference, which is due to end Dec 18.