In a special alert, the UN agency advised that prolonged dry weather in spring in the main cereal‐producing provinces has raised serious concerns about staple crop production.
"Should drought conditions persist, the food security situation is likely to further deteriorate,” the alert added.
North Korea has been blighted by poor harvests and famines since the late Nineties, when at least 2m people died from malnutrition. The UN's World Food Programme estimates 70% of the country's 25m people still do not eat a "sufficiently diverse diet."
From April until late June rainfall in some of the key cereal-growing regions was half the long-term average.
The severe dry spell also affected this year’s early-season crops, which include wheat, barley and potatoes. According to FAO's latest estimates, production of these has plunged by over 30%, from last year's level of 450,000 tonnes to 310,000 tonnes.
Despite the fact that the early season harvest accounts for only 10% of the total annual cereal production, these crops are an important source of food during the lean season from May to September.
"Seasonal rainfall in main cereal-producing areas has been below the level of 2001, when cereal production dropped to the unprecedented level of only 2m tonnes," Vincent Martin, the FAO’s representative in China and North Korea, said.
The UN organisation has called for immediate assistance for the country's population, including irrigation equipment and food aid.
"It is recommended to introduce longer-term measures to increase farm and household resilience to natural disasters and climate change," the alert said, referring to North Korea's susceptibility to flooding.