ROME, Italy (AFP)— Nearly half of Haiti's population, 4.9 million people, are struggling to feed themselves -- three time the number in 2016, the UN's food agency warned Thursday.

Soaring inflation has made basic food items unaffordable for many in the Americas' poorest nation, the World Food Programme (WFP) said.

In addition, gang violence in the capital Port-au-Prince has restricted movement and access to food, water and sanitation, while the spread of armed groups to agricultural areas "is further cause for alarm", the WFP said.

More than 530 people have been killed this year in gang violence in Haiti, the UN human rights office said Tuesday.

The WFP said humanitarian support was making a difference, but appealed for $125 million to support its programmes in Haiti for the six months.

"Haiti can't wait," said WFP country director Jean-Martin Bauer.

"We cannot wait for the scale of the problem to be expressed in deaths before the world responds. But that is where we are heading."

The latest WFP assessment classified 31 percent of Haiti's population as Phase 3 in the internationally-recognised Acute Food Security scale, meaning they exist on the minimum of food and suffer high rates of malnutrition.

Another 18 percent are in Phase 4, classed as an emergency -- just one level above famine.