Malnourished children are flooding into the paediatric ward of the main hospital in Ethiopia's Gode city as the worst drought in 40 years has forced many families to leave their homes to search for aid.

On Tuesday, Reuters saw a dozen malnourished children in Gode General Hospital. Paediatrician Mohammed Amin said that numbers started to spike around five months ago.

"So far, we have treated 140 malnourished children and from this four have died," he said. "This figure is only those who came to us and got treatment and doesn’t include those in the camp."

Last year, the hospital received 188 malnourished children, but now they saw that in a single month, he said, adding that many families were arriving with several malnourished children.

The Horn of Africa region is facing the driest conditions in more than four decades after three consecutive rainy seasons failed, according to the United Nations' World Food Programme (WFP).

The WFP said around 15 million people need food in the Horn of Africa, a figure that could rise to 20m by the end of the year.

"There’s been a series of climate shocks which has compounded the food insecurity situation," said Claire Nevill, spokeswoman for WFP.

Many families have left their homes to seek aid. Nimo Mohammed, a 35-year-old mother of nine who is about to have another baby, now lives with her entire family in a camp in Ethiopia's southeastern Somali region.

More than 10,000 people are getting aid there — most of them women and children. They are living in makeshift houses made of sticks and covered with plastic sheets or clothes.

"This drought has knocked out me and my entire family,” Nimo told Reuters. "Maybe our children eat once a day but the adults we may not eat for days so that the children can eat."