The number of people without enough to eat on a daily basis reached an all-time high last year and is poised to hit "appalling" new levels as the Ukraine war affects global food production.
Almost 193 million people in 53 countries suffered acute food insecurity in 2021 due to what the UN said was a "toxic triple combination" of conflict, weather extremes and the economic effects of the coronavirus pandemic.
The UN said the number of people without adequate food every day increased by 40 million last year, confirming a "worrisome trend" of annual increases over several years.
The figures appeared in the Global Report on Food Crisis, which is produced jointly by the UN Food and Agriculture Organisation, the World Food Program and the European Union.
Countries experiencing protracted conflicts, including Afghanistan, Congo, Ethiopia, Nigeria, South Sudan, Syria and Yemen, had the most food-insecure populations, according to the report.
The report forecasts Somalia will face one of the world's worst food crises in 2022 due to prolonged drought, increasing food prices and persistent violence.
The various factors could lead six million Somalis into acute food crisis, the UN said.
"If more is not done to support rural communities, the scale of the devastation in terms of hunger and lost livelihoods will be appalling," the UN said.
"Urgent humanitarian action is needed on a massive scale to prevent that from happening."
The war in Ukraine poses further risks for Somalia and many other African countries that reply on Ukraine and Russia for wheat, fertiliser and other food supplies.
WFP's Chief Economist Arif Husain said the UN food agency projects an additional 47 million people will become food insecure "in crisis or worse situation" because of the war in Ukraine as a result of higher food and fuel prices and inflation.
Even before the war, people were dealing with the consequences of the COVID-19 pandemic and reduced incomes.
Food prices were at a 10-year high and fuel prices at a seven-year high, Mr Husain told reporters at UN headquarters in New York at a virtual press conference.
"This crisis is potentially more fuel on a fire which was already lit and burning up," he said.
The United Nations previously said the war was helping to send prices for commodities such as grains and vegetable oils to record highs, threatening millions with hunger and malnourishment.
The virtual UN briefing was told the percentage of the population analysed in the report who are in acute food insecurity went up from just over 11 per cent in 2016 to just over 22 per cent in 2021.
In 2021, $US8.1 billion ($A11.2 billion) was available for emergency work, a 25 per cent drop from 2017.
The report called for greater investment in agriculture and appealed for $US1.5 billion ($A2.1 billion) to help farmers in at-risk regions with the upcoming planting season.
WFP's Husain said his message to rich nations in the G7 and G20 is that food insecurity and hunger around the world are "exploding" and "if we don't address these issues we end up paying frankly a thousand times more just a few years down the road."