By Imogen Foulkes
BBC correspondent in Geneva
A United Nations agency says it is concerned at growing levels of despair among refugees in the occupied territories.
Unrwa says malnutrition is a certainty
Speaking in Geneva, Peter Hansen, the head of UN Relief Agency for Palestinian Refugees (Unrwa), appealed for greater commitment from the international community.
He warned that unless the refugees were given some reason to hope for an improvement in their lives, they would be unlikely to have faith in the Middle East peace process.
The mood among Palestinian refugees is, he said, one of growing "hopelessness, cynicism and despair".
The agency believes that if the refugees are not given some reason to hope for an improvement in their situation, they will lose faith in the international community.
But Unrwa is under-funded. It has cut its emergency food distribution in the occupied territories from 60% to 40% of daily requirements, and will have to cut it again to 20%.
Malnutrition is, the agency says, a certainty.
Mr Hansen said the building of the security barrier, which Israel says it needs to protect itself from attacks by suicide bombers, is already adding to the problems, not just because people are cut off from their jobs or their land, but because Palestinians see the barrier as another sign that their situation is hopeless.
"They see this fence as being the future border where less and less of their land is apparently going to be left for them," said Mr Hansen.
Israel's barrier is a source of despair, says Unrwa
"That's how they read the wall, and that's how many observers read the wall, even though the Israelis are saying that that can be changed at any moment. It looks massive enough to me to appear to be difficult to move just like that."
Unrwa has announced it will hold a conference in Geneva in June to discuss humanitarian assistance to Palestinian refugees.
Up to 70 countries and aid organisations are expected to attend - the first time in Unrwa's 54-year history that such a meeting has been held.
It is, Unrwa says, a chance for donor countries to recommit themselves and will be an important sign to the refugees that they have not been forgotten.