Unicef says nearly a million children have been "severely" affected by the Nepal earthquake.
More than 3,300 people are now known to have died in Saturday's disaster, while more than 6,500 have been injured.
Hundreds of thousands of people are now sleeping in open areas out of fear of more tremors - while heavy rain is expected to disrupt rescue efforts in the coming days.
Jack Hogan, Communications Director of the Umbrella Foundation in Kathmandu, says shelter and clean water are now the priority.
He said: "It's more so the aftermath than the initial earthquake that we have to be worried about, the spread of disease, even crime. There has been no sign of that yet thankfully, but we do need to be prepared.
"The umbrella foundation has enough drinking water to last for the next couple of days, but thereafter we are not so sure."