Official rations are down to 300 grammes - under 11 ounces - per person per day, the lowest ever for this time of year, the U.N. said following a food security assessment it carried out at Pyongyang's request from March 29 to April 12.
It found that 10.1 million people were suffering from severe food insecurity, "meaning they do not have enough food till the next harvest," U.N. World Food Program spokesman Herve Verhoosel said.
North Korea's population is around 25.2 million, according to its Central Bureau of Statistics, the report said.
Verhoosel said the word "famine" was not being used in the current crisis, but it might come to that in a few months or years. "The situation is very serious today - that's a fact."
The country suffered a famine in the mid-1990s believed to have killed as many as 3 million people.