Brazzaville - Congo and several UN agencies have launched a joint appeal for $23.7m to help 138 000 people hit by fighting and insecurity in the southern region of Pool.
"The most pressing humanitarian needs are related to food security, nutrition, living conditions and access to basic health services," said OCHA, the UN agency that coordinates humanitarian work.
They were vulnerable to attacks, threats, sexual violence, loss or family separation, said the statement, issued on Tuesday.
Deadly violence broke out in the Pool region, which adjoins the capital Brazzaville, following Denis Sassou Nguesso's re-election as president in March 2016.
According to UN figures, one in three persons there were forced to flee the unrest. And a report by the World Health Organisation said more than 17% of under-fives forced to flee were suffering from malnutrition.
Voting in the first round of parliamentary elections last weekend had to be postponed in eight out of 14 constituencies.
Rights groups had said earlier that it was impossible for people forced to feel the violence there to vote.