The long queue of anxious parents waiting outside paediatrician Rajaa Okasha's tent shows how badly his voluntary services are needed after four months of an Israel assault on Gaza that has been especially hard for children.

Working all day under canvas on the sandy ground with hardly any medicine available, he does what he can for an endless line of sick and injured children living through a war that has made almost everyone in the enclave homeless.

Okasha is homeless himself after fleeing his home in Beit Hanoun, the first place targeted by Israel's ground offensive, and like the majority of Gazans has ended up in Rafah on the border with Egypt.

"When I see a child, I feel the need to offer him treatment and to try and help him," Okasha said, explaining why he had set up a tent as a free medical centre for children in the part of Rafah where he is sheltering.

A nurse bandages a toddler's foot, a mother with an exhausted, careworn face cradles her baby, a blonde girl stares out from around a tent flap and there is a constant sound of fussing and crying.

Israel's war in Gaza was triggered by the Oct. 7 Hamas attack, when the group's fighters rampaged across the border fence, killing 1,200 people and dragging another 250 back as hostages according to Israeli tallies.

The Israeli military's air and ground assault on Gaza has since killed more than 28,000 Palestinians say health authorities in the Hamas-run enclave while causing untold devastation and a humanitarian catastrophe.

As Okasha examines a screaming baby, squirming with discomfort, a line of parents extends from his desk back through the tent and out into the busy Rafah area where it stands near market stalls.

Israel has said it plans to extend its military campaign into Rafah, where more than a million displaced people have crammed, leading aid agencies to warn an assault on the city would cause utter catastrophe.

DISEASE WIDESPREAD IN GAZA

Okasha in his blue scrubs and with a stethoscope around his neck presses a thermometer to a child's ear. After working in a hospital before the war he relies on donations for the little equipment he has.

"Diseases are widely spread among children in a scary way - especially intestinal infections, viral infections, respiratory infections because of the cold," he said.

He sees children coming in without adequate clothing and their parents tell them they have no money for more. Most concerning, hepatitis A is becoming rife, he says.

"This is all because of a lack of cleanliness," he says, pointing to the absence of clean water for drinking or cleaning. Many people in Gaza have been reduced to washing in seawater and drinking brackish, salty water pumped from wells.

Very often, all he can do is prescribe painkillers - which are often absent from pharmacies anyway.

"My son is very sick. He has a fever and diarrhoea caused by the tough living conditions in the war," said Ahmed al-Amodi, holding his crying son.

Most of Gaza's hospitals have stopped working, with some damaged by Israeli bombardment and those still functioning under growing pressure as Israeli troops push closer. Israel says Hamas uses such facilities as cover for military purposes, which the group denies.

The World Health Organisation has said only 15 of Gaza's pre-war 36 hospitals are still partially or minimally functioning and a U.N. survey has found that nearly one in 10 children under five are acutely malnourished.

(Reporting by Saleh Salem; Writing by Angus McDowall; Editing by Alison Williams)