Two and a half million people in the Central African Republic, half the population, have too little to eat because of conflict and insecurity, and the number has doubled in the past year, the United Nations World Food Programme (WFP) said on Wednesday.

The former French colony, a majority Christian nation, descended into turmoil in early 2013 when mainly Muslim Seleka rebels seized power, provoking reprisals by Christian militia fighters.

Almost half a million people fled their homes and remain displaced within the country, while more than 450,000 have fled to neighboring countries, according to the UN Office for the Coordination of Humanitarian Affairs (OCHA).

"Three years of crisis have taken a huge toll on the people of the CAR," WFP deputy country director Guy Adoua said in a statement.

"Families have been forced so often to sell what they own, pull their kids out of school, even resort to begging, that they have reached the end of their rope. This is not the usual run-of-the-mill emergency. People are left with nothing."

The 2014-2015 harvest was poor and food prices remained high because it was too dangerous for farmers to tend their fields, he WFP said.

One in six Central Africans are struggling with extreme food insecurity, meaning having to sell their possessions just to get by, and more than one in three do not know where their next meal is coming from, the WFP said.

"WFP is extremely concerned by this alarming level of hunger," Adoua said. "People not only lack enough food but are also forced to consume low-cost, low-nutrient food that does not meet their nutritional needs."

WFP said it was providing food and nutritional support through food distributions, cash transfers, school meals and other activities and in December it provided food for nearly 400,000 people.

The agency said its operations were only 45 percent funded and it needed $41 million to meet urgent needs through to the end of June in Central African Republic and those of its neighbors hosting Central African refugees.