"Given the tight food supplies in 2015/16, the country's food security situation is expected to deteriorate from the previous year when most households were already estimated to have poor or borderline food consumption levels," the agency said in a report on Wednesday.
North Korea's total food production fell 9 percent on-year to 5.4 million tons in 2015, with the harvest of rice — a food staple — dropping 26 percent due to poor rains and a lack of irrigation, the FAO said.
It was the country's first decline in total food production since 2010, the agency added.
The FAO's country monitor, Cristina Coslet, said in a video that the agency was concerned about the expected drop in food production this year, particularly as public rations for 18 million people, or more than two-thirds of the population, had already "decreased considerably" since July 2015.
In recent years, most households in North Korea have poor or borderline food consumption rates, she added. In 2015 there were reports of North Koreans, particularly soldiers, crossing the border into China in search of food.
Reduced fertilizer and fuel supply last year also limited crop production, the FAO said.
A strong ongoing El Nino weather phenomenon is causing hot, dry weather in the Asia Pacific, hitting food crops such as palm oil in Southeast Asia and wheat in Australia.
But it's not just the weather North Korean's need worry about; in March a North Korean newspaper warned citizens to prepare for economic hardship ahead, as the rogue nation channeled funding into its weapons program.