BBC-Aid agencies working in the world's largest refugee camp in Kenya say they are running out of funds, putting tens of thousands of lives at risk.
Eight organisations, including Oxfam and Save the Children, say they are facing a shortfall of $25m (£16m), but that the need is greater than ever.
The population at Dadaab, which lies near the Somali border, has increased by a third over the past year.
It is now home to almost half a million people.
The BBC's world affairs correspondent Mike Wooldridge says that, according to the aid agencies, many refugees are still in tents that are quickly destroyed in the harsh climate.
The aid agencies say that 30,000 new shelters are needed, but that funding is available for only 4,000.
Also at risk is the provision of water supplies and sanitation for some 50,000 refugees, leaving them at risk from cholera, they say.
The agencies say long-term solutions for those living in the overcrowded camp are needed.
According to Stephen Vaughan, head of CARE Kenya, people who had fled terrible suffering are not getting the care they needed.
"As well as the human cost, there is also a cost to security in the region," he said.
"If children are not going to school and if people do not have proper shelter and other services, this has the potential to fuel further militarisation, violence and instability."
Nigel Tricks, head of Oxfam in Kenya, said: "Refugee camps are only temporary solutions and the situation is increasingly untenable. Funds are needed now to save lives, but we can't keep pumping money in year after year while the camp keeps getting bigger.
"A change in approach is urgently needed. However, right now, the world has an obligation not to turn its back on Dadaab and the needs of the people there."
Last October, gunmen kidnapped two Spaniards working for Medecins Sans Frontieres (Doctors Without Borders) at the Dadaab camp. They are still being held hostage in Somalia.
Somalia has not had a functioning central government for more than 20 years and has been racked by fighting between various militias.