Click here for Al Jazeera's extensive coverage
Officials from 10 U.N. agencies, the International Organization for Migration and 18 other aid groups met in Amman, Jordan, on Sept. 26 to plan their response to the crisis for 2014.
"The most likely scenario was perceived to be continuation and escalation of the conflict, with increased fragmentation, disruption of essential services and further erosion of coping mechanisms," an official from the U.N. Office for the Coordination of Humanitarian Affairs told the meeting.
The OCHA forecast that up to 8.3 million people would be in need by the end of 2014 — more than a third of Syria's prewar population of 23 million and a 37 percent increase from 2013 — including 6.5 million internally displaced people.
The number of refugees was expected to hit 3.2 million by the end of 2013 and rise an additional 2 million next year, the summary said.
The bulk of Syrian refugees have so far been registered in Lebanon, Jordan, Turkey and Iraq.
In the absence of any solid prospects for peace in a war that has killed more than 100,000 people, U.N. agencies have begun shifting the focus of aid planning from an emergency response to helping Syria and its neighbors meet huge humanitarian needs in the long term.
A planned international conference to end the conflict has been repeatedly postponed and is now penciled in for mid-November.
Al Jazeera and Reuters