North Korea's already-low food supply is set to deteriorate this year as dry weather hits crop yields, the United Nations' Food and Agriculture Organization (FAO) has warned.

"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.