The earthquake in Nepal has impacted eight million people in 39 districts, of which over two million live in 11 most severely affected districts, the UN said on Tuesday.
The immediate priority of the victims include food, water, shelter and medication, the UN said, adding 1.4 million people were in urgent need of food assistance.
Three quarters of the affected population was outside of Kathmandu, among the worst hit areas.
The UN said that rains predicted over the next 10 days would add to human misery, hampering relief efforts. It could also lead to diseases.
The impact on agriculture based livelihood and food security was expected to be "extremely high", it said.
The people's immediate needs include medical tents, medication, surgical kits and body bags.
An earthquake measuring 7.9 on the Richter scale jolted Nepal on Saturday killing nearly 4,500 people and injuring thousands.