Spilling into the hallways of crowded Yemeni hospitals, children writhe in pain from cholera.

Displaced villagers roam baking hot plains and barren mountains to evade warring militias.

The escalating outbreak of disease and displacement of tens of thousands by recent fighting has inflamed one of the world's worst humanitarian crises, pushing Yemen's war-pummeled society ever nearer to collapse.

Cholera - a diarrhoeal disease spread by food or water tainted with human faeces - has killed 180 people in less than three weeks, according to the Geneva-based International Committee of the Red Cross (ICRC).

Samira Ali, a worried mother, expressed shock at the scene at Sabaeen Hospital in Sanaa, the ancient capital in the north held by the armed Houthi movement since late 2015.

"My young son suddenly started suffering from severe diarrhoea. We went to the hospital and found it full, we couldn't find a place," said Ali, a teacher.

"Only with difficulty were the doctors able to give him the medicines which saved his life. This situation is tragic."

The United Nations now estimates that in Yemen a child under the age of five dies every 10 minutes from preventable causes, two million people have fled fighting near their homes and only half of hospitals have staff and supplies to function normally.

Already one of the poorest countries in the Middle East, Yemen was engulfed in 2015 by civil war pitting the Houthis against the internationally recognised government of President Abd-Rabbu Mansour Hadi.