The UN's World Food Programme (WFP) is to deliver emergency aid to the south-east of Cuba, where Hurricane Sandy wrought widespread damage.
It was "the worst catastrophe in 50 years in Santiago de Cuba," WFP spokeswoman Elisabeth Byrs said.
The WFP is also appealing for $20m (£12.5) to help some 425,000 Haitians affected by the storm.
Sandy caused widespread damage to infrastructure, crops and livestock in both Haiti and Cuba.
The WFP is planning to work with the Cuban government to distribute emergency one-month aid in Santiago de Cuba, which is home to 500,000 residents.
The hurricane, which hit Cuba on 25 October and left 11 people dead, brought down many buildings and knocked out the electricity.
Cuban President Raul Castro is in Santiago to oversee recovery efforts and has promised to remain until the power is back on.
In the city, much of the debris has been cleared from the streets and pupils have returned to classes, although not all are being held in actual school buildings.
According to initial government reports, Sandy damaged some 200,000 homes and affected more than a million people.
"We are especially concerned about the damage in the agricultural sector where tens of thousands of hectares of staple crops have been affected," said WFP emergency co-ordinator William Vigil in a statement.
Help would continue until production capacities were restored, he said.
The WFP is also seeking funds to help Haiti, where more than 50 people died in the storm.
Sandy's winds and rains destroyed many of the crops in the south of the country.
The WFP calculates that nearly two million people are facing food insecurity in Haiti.
The situation was already precarious in the wake of the 2010 earthquake and a drought.