"We must prevent the Central African Republic from becoming a forgotten crisis," said Claire Bourgois, the UN humanitarian coordinator for the country.
CAR is struggling to recover from the coup that ousted president Francois Bozize in March 2013 and triggered a wave of deadly sectarian violence between the country's Christian and Muslim populations.
Now, a transitional government faces the uphill task of rebuilding a shattered administration. But it is almost entirely dependent on foreign funds, and the economy is in ruins.
About half the population of 4.6 million people live in severe poverty and need humanitarian aid, while 1.5 million are considered food insecure, according to the UN.
Lawlessness meanwhile continues to affect many of the country's regions, with continuing violence forcing some 50,000 people to flee to neighbouring countries since last December and displacing more than 20,000 more inside the country.
Since December 2013, nearly 900,000 people have been displaced, including more than 460,000 who have become refugees -- a full 10 percent of CAR's population.
Yet despite the massive crisis, the UN humanitarian agency OCHA has so far received only 14 percent of the $613 million it says it needs to address the crisis inside CAR this year.
The UN refugee agency UNHCR has meanwhile pulled in only nine percent of the $331.2 million it has appealed for to help refugees and host communities in neighbouring countries in 2015.
"We are making a strong plea to the donors," Liz Ahua, the UN refugee agency's regional coordinator, told reporters in Geneva.
The lack of funds means that UN agencies are unable to address all of the numerous needs.
CAR refugees in Chad are for instance receiving just half food rations, meaning they are living on half the calories deemed necessary to stay healthy, Ahua said.
The lack of funds this year has been compounded by years of underfunding.
"If the country has so many humanitarian needs, it is because it has been forgotten for years before, and crisis after crisis has just (left) this country more in the dark," Bourgois told reporters.