JERUSALEM (AFP) - Israel's 24-day-old Gaza offensive has spawned a humanitarian crisis of monstrous proportions, prompting a home-grown pop star and the overstretched UN relief agency he represents to appeal for aid.

"There is pain in my heart from what is happening in my town and to my people in my beloved home, Gaza that is hurting," said Khan Yunis-born Mohammed Assaf, winner of the popular Arab Idol talent show, in a video distributed by the United Nations on Thursday.

"Now we all have to help my beloved people in Gaza, all those who suffer in Gaza, all those who suffer under the attacks," said Mr Assaf, who accompanied an airlift of humanitarian supplies from Dubai to Jordan, from where it continued to Gaza by road.

"We have to help Gaza stand up on its feet one more time," added Assaf, who is the goodwill ambassador of UNRWA, the UN agency for Palestinian refugees.

UNRWA's spokesman in Gaza, Chris Gunness, broke down in tears on Wednesday when Al-Jazeera television interviewed him after 16 people died in the shelling of a UN school in Gaza.

"The rights of Palestinians, even their children, are wholesale denied and its appalling," MNr Gunness said in a voice choked with emotion, before burying his face in his hands and sobbing uncontrollably.

The agency has declared a state of emergency and launched an appeal for funding.

"UNRWA urgently seeks US$60 million (S$75 million) to respond to the immediate shelter, food, health and psycho-social needs of affected families; to replenish emergency stocks; and to prepare for carrying out vital interventions that will be required immediately upon cessation of military activities," its website said.

UNRWA chief Pierre Kraehenbeuhl told the Security Council on Thursday that the agency was stretched to breaking point by the massive humanitarian fallout from the fighting in Gaza.

"I believe the population is facing a precipice, and appeal to the international community to take the steps necessary to address this extreme situation," he said.