Most have fled from violence in the economic capital of Abidjan, the BBC reported Saturday.
The violence is the result of a disputed presidential election that was supposed to unite the West African country but instead has resulted in dozens of deaths in the world's largest cocoa-producing nation.
Most of the world recognizes Alassane Ouattara as the winner of November's election, but incumbent President Laurent Gbagbo refuses to step down.
France has circulated a draft resolution at the United Nations calling for sanctions against Gbagbo.
"The massive displacement in Abidjan and elsewhere is being fueled by fears of all-out war," said spokeswoman Melissa Fleming at refugee agency's headquarters in Geneva.
The refugee agency also said mercenaries from neighboring Liberia are entering Ivory Coast to take advantage of the political chaos. It said they are looting, raping and killing people in the Guiglo region.