The WHO has warned the health situation in the West Bank and Gaza has reached a critical point and could slide into collapse without further assistance.
By Imogen Foulkes
BBC correspondent in Geneva
Dr David Nabarro, the WHO's director for health in crisis situations, has just returned from a fact-finding trip to the Palestinian territories.
At the annual assembly in Geneva he said there were signs the situation was becoming increasingly precarious.
Malnutrition was rising and vaccination levels were falling, he said.
People with diseases such as diabetes were not getting the treatment they require, he added.
These are all indicators the WHO has observed in other crisis regions and they are frequently the precursors of a general collapse of the healthcare system.
Concern for children
The Palestinian territories do benefit from generous medical aid and highly skilled doctors and nurses, but the increasing restrictions on movement caused by checkpoints and by the new security barrier mean that often medical supplies are not getting through.
Patients cannot get to hospital and medical staff cannot get to work.
The WHO is especially concerned for the health of very young children, the elderly and people with chronic diseases.
These three groups account for almost 25% of the population.
An international conference of donor countries will discuss aid to the West Bank and Gaza in Geneva at the start of June and health will be a top priority.
On Thursday the assembly passed a resolution calling for the WHO director general to send a team to the occupied territories to assess what it called the degradation of the health services resulting from the current crisis and from Israel's security barrier.