Palestinians are dying every day in Gaza's overwhelmed remaining hospitals which can't deal with the tens of thousands people hurt in Israeli's military offensive, a UN health emergency expert said Wednesday, while a doctor with the International Rescue Committee called the situation in Gaza's hospitals the most extreme she had ever seen.

The two health professionals, who recently left Gaza after weeks working in hospitals there, described overwhelmed doctors trying to save the lives of thousands of wounded people amid collapsing hospitals that have turned into impromptu refugee camps.

The World Health Organization's (WHO) Sean Casey, who left Gaza recently after five weeks of trying to get more staff and supplies to the territory's 16 partially functioning hospitals, told a UN news conference that he saw "a really horrifying situation in the hospitals” as the health system collapsed day by day.

Al-Shifa Hospital, once Gaza's leading hospital with 700 beds, has been reduced to treating only emergency trauma victims, and is filled with thousands of people who have fled their homes and are now living in operating rooms, corridors and stairs, he said.

“Literally five or six doctors or nurses” are seeing hundreds of patients a day, Casey said, most with life-threatening injuries, and there were “so many patients on the floor you could barely move without stepping on somebody's hands or feet.”

The Health Ministry in Hamas-run Gaza estimates that 60,000 people have been wounded, with hundreds more wounded per day.

Since Israel declared war against Hamas following its surprise attacks into the country's south on October 7, it has repeatedly accused the Islamic militant group of using Gaza's hospitals as cover for military activities. It singled out Al-Shifa in Gaza City, saying Hamas had hidden command centres and bunkers underneath the hospital's sprawling grounds. In late November, the Israeli military unveiled what it claimed was a Hamas military facility under the hospital.

Casey said he was able to reach Al-Shifa three times with deliveries of medical supplies, fuel and food, but once it took 12 days because of Israeli refusals, mainly for security or operational reasons.

At Al-Ahli Hospital, also in Gaza City, the situation was also dire, he said.

“I saw patients who were lying on church pews, basically waiting to die in a hospital that had no fuel, no power, no water, very little in the way of medical supplies and only a handful of staff remaining to take care of them,” he said.

Last week, Casey said, he visited the Nasser medical complex, the main hospital in Khan Younis, which is at 200 per cent of its bed capacity with only 30 per cent of its staff, so “patients are everywhere, in the corridors, on the floor.”

“I went to the burn unit where there was one physician caring for 100 burn patients,” he said.

Even in Rafah in the south near the Egyptian border, where Israel has urged Gazans to move, Casey said the population has skyrocketed from 2,70,000 a few weeks ago to almost a million, and the city doesn't have the health facilities to deal with the massive influx of displaced people.

Gaza historically had a strong health system with 36 hospitals, 25,000 health workers and many specialists, he said, but 85 per cent of the territory's 2.3 million people are now displaced, and that includes health workers, doctors, nurses, surgeons and administrative staff.

Casey said many of these medical professionals are in shelters, under plastic sheeting on streets in Rafah, and not in hospitals. One hospital director told him his plastic surgeon couldn't do surgery because he was out collecting sticks to burn as firewood to cook food for his family.

What's needed first and foremost to help the tens of thousands of injured Gazans and people with health issues is a ceasefire and the safety and security that would bring, Casey said, but that's not enough.

“It's really the overall package,” he said, saying medical supplies first need to overcome obstacles and inspections and get into Gaza, and then they need to get to the hospitals where they're needed.

But without health workers, medical supplies, and fuel to run the generators at hospitals and health facilities, “you can't do the surgeries, you can't provide the postoperative care,” he said.

Casey said the World Health Organization is trying to mobilize international emergency medical teams to support Gaza's hospitals and provide care. It has also supported the establishment of several field hospitals over the last six weeks or so, he said.

“The numbers of medical evacuations going outside of the Gaza Strip is very limited,” he said. “We know that there are thousands of people who would benefit from higher-level care that can no longer be provided within the Gaza Strip,” including cancer patients and people with complex injuries.

“People are dying every day,” Casey said. “I've seen children full of shrapnel dying on the floor because there are no supplies in the emergency department, and the health care workers ... to care for them.”

Speaking at another press briefing, Dr Seema Jilani, a pediatrician and the International Rescue Committee's senior technical advisor for emergency health, said she just went to Gaza for two weeks in collaboration with Medical Aid for Palestinians and what she saw was “harrowing, and scenes out of nightmares.”

Jilani, who previously worked in hotspots including Afghanistan, Iraq and Lebanon, said “In my experience of working in conflict zones around the world, this is the most extreme situation I have seen in terms of scale, severity of injuries, number of children that have suffered that have nothing to do with any of this.”

Jilani worked in the emergency room at Al-Aksa Hospital in Deir al-Balah, the only hospital in the middle area of Gaza. On her first day, she said, she tried to save an approximately 1-year-old boy whose right arm and right leg had been blown off, without any of the necessary medication. Next to him was a dying man with "flies ... already feasting on him,” she said.

Jilani said she treated children with injuries from traumatic amputations to extreme burns, sometimes seeing the smoke from nearby Israeli bombings. “And one day a bullet did indeed go through the intensive care unit.”

After she left, Jilani said, the hospital ran out of fuel and the lights went out. She doesn't know how the babies she treated are doing, or whether they were evacuated.