(CNN) -- The largest refugee camp in the world, in Dadaab, Kenya, is facing an overcrowding crisis with at least 700 families now residing in "unacceptable living conditions" outside the camp and in peril with the approaching rain season, the humanitarian group Medecins Sans Frontieres (Doctors Without Borders) said.
The overflowing refugee camp -- accommodating almost 300,000 Somali refugees though it was built for only 90,000 -- is now seeing "spontaneous settlements" of at least 3,000 people living in makeshift shelters, the group said Friday. Those 3,000 people couldn't find room in the three camps that make up the Dadaab compound, including the 700 families outside the Dagahaley camp, the group said.
Medecins Sans Frontieres on Friday called upon the international aid community and Kenyan authorities to reach an agreement to provide assistance to the families, as heavy rains the past two days have flooded the settlements.
"Hundreds of families have been living in makeshift shelters in a no-man's land over the past four months, waiting to be re-located to a proper camp," said Joke Van Peteghem, the group's head of mission in Kenya. "These refugees are in dire need of assistance given the hardships they have endured. With the onset of the rainy season, we must act now."
The dire conditions have long been documented by the United Nations Human Rights Council, which in May described services as "stretched to their limits" and unacceptable conditions that included a "growing risk of and vulnerability to disease."
"We are at a dead end," said Van Peteghem. "While we have distributed plastic sheeting to the new refugee families, it is far from enough, especially now that the rainy season has started."
Thousands of men, women and children flee by foot the war in Somalia each month, making a treacherous journey into Kenya, but they arrive to the refugee camps finding shortages of water, food, sanitation and shelter, Medecins Sans Frontieres officials said.
The camp complex is so overcrowded that it cannot accept hundreds of families, group officials said.