The Food and Agriculture Organization (FAO) said about 7.7 million people were on the verge of starvation overall.
“Food security and nutrition... are deteriorating in many parts of DRC, but nowhere is the situation more alarming than in Kasai," said Claude Jibidar, director of the World Food Programme's operations in the country.
The Food and Agriculture Organization (FAO) said about 7.7 million people were on the verge of starvation overall in the vast central African country, a 30 percent surge over a year ago.
A rebellion has been raging in the diamond-rich Kasai region for the past year, with both the government and rebels accused of atrocities.
The FAO said an estimated 1.4 million people in Kasai and in the eastern province of Tanganyika had been forced to flee their homes over the past year.
Farmers have been unable to plant their crops for the last two seasons because of fighting that has seen their villages and fields pillaged, the report says.
In addition, armyworm infestations have destroyed crops in over a quarter of the country, it said.
"The situation is set to get worse if urgent support does not come in time," said Alexis Bonte, the FAO's representative in the DRC.
"Farmers, especially those displaced -- majority women and children -- desperately need urgent food aid but also means to sustain themselves, such as tools and seeds so that they can resume farming," he said.
Chronic malnutrition affects 43 percent of children under five -– or more than seven million children -– overall in DR Congo, the FAO report said.
Conflicts have displaced about 3.7 million people within the country, with "a steady flow of refugees from neighbouring countries putting a strain on already stretched resources", it said.