The agencies fear that efforts to prevent the crisis from deteriorating will falter as rival sides regroup ready to resume violence once the rainy season ends. The number of people facing dangerous levels of hunger is expected to increase by 1 million between January and March 2015.
The report calls for neighbouring governments and the wider international community to redouble diplomatic efforts to put real pressure on the parties to the conflict to end the fighting, including an arms embargo.
The agencies also call for an increase in both the quantity and quality of the aid effort.
