The residents of Gaza are facing severe shortages of food in the besieged coastal region that has been in the middle of a grinding Israeli genocide for more than 600 days.

As hunger grows, hundreds of desperate Palestinians swarmed a United Nations warehouse on Wednesday in search of food.

A day earlier, a crowd was fired upon by Israeli military while overrunning an aid distribution site set up by a new but controversial foundation backed by Israel and the United States.

Palestinians and the UN have rejected that new system, saying it cannot meet the needs of Gaza's over 2 million starving people.

Until last week, Israel kept food and other supplies from entering Gaza for nearly three months as part of its annihilation campaign.

Here is a story of a Palestinian man who described 15 minutes of terror trying to get food in the new Gaza distribution system.

Shehada Hijazi woke at dawn. It was his best chance, he thought, to get his hands on a package of food at a new distribution site run by a controversial US and Israeli-backed foundation in Gaza.

Thousands of others, equally desperate to feed their hungry families, had the same idea.

By the time Hijazi walked the 7 kilometres to the southern tip of the territory, a militarised zone that has been cleansed of its residents, it was chaos.

People pushed and shoved for hours as they restlessly waited outside the site, surrounded by a barbed-wire fence, earth berms and checkpoints.

When it opened, the crowd charged, rushing toward hundreds of boxes left stacked on the ground on wooden pallets.

Hijazi described what he called 15 minutes of terror on Thursday at the centre run by the Gaza Humanitarian Foundation, the private contractor that Israel says will replace the UN in feeding Gaza's hungry people.

Israeli soldiers opened fire in an attempt to “control” the crowd. His 23-year-old cousin was shot in the foot. They quickly abandoned hope of getting any food and ran for their lives.

The "gunfire was very intense.... The sand was jumping around us," he told The Associated Press.

On Friday, Hijazi said he would wait before returning, though he is desperate for anything to feed his extended family — now about 200 members living together in a displacement camp in the southern city of Khan Younis.

"Hunger has hit home. I can't wait around to watch my family die of hunger," the 41-year-old said.

It's a reality faced by hundreds of thousands of Palestinians, plagued by rising hunger and malnutrition after a nearly three-month Israeli blockade barring all food and supplies from Gaza.

Multiple witnesses have reported Israeli troops opening fire at GHF centres.

At least six people were killed and more than 50 wounded around the sites, according to Dr. Ahmmed al-Farrah at Khan Younis' Nasser Hospital, where casualties were taken.

"This farce and humiliation are by design," Hijazi said.

The UN and other aid groups have refused to participate in the GHF system saying it violates humanitarian principles.

They say it puts aid under Israel's control to use to carry out its announced plans to move Gaza's entire population to the south.

They also say it cannot meet the massive needs of the population and endangers those seeking food.

There have been unruly crowds around Gaza's communal kitchens, but scenes like those at GHF hubs have been rare at UN distribution sites.

The UN and other aid groups have run hundreds of distribution points around Gaza and often use a coupon system to organise when families pick up aid — to ensure it is handed out equitably and to avoid large crowds at a single location.

A few times, hungry crowds have broken into aid warehouses, when the flow of aid has plunged particularly low, usually because of Israeli military restrictions, UN workers say.

The UN says such attacks virtually stop when the aid flow is well.

"People don’t understand why it is difficult to give out food" in crises, said Ruth James, humanitarian coordinator for Oxfam.

Managing large crowds and preventing stampedes takes planning and clear communication, she said. In a crowd, usually the most powerful get to the food or parcels, and the people most in need are overlooked.

The situation in Gaza is the worst since Israel's genocidal war began 19-months ago, the United Nations said on Friday, despite a resumption of limited aid deliveries in the Palestinian enclave where famine looms.

"Any aid that gets into the hands of people who need it is good," UN spokesperson Stephane Dujarric told reporters in New York. But, he added, the aid deliveries so far overall have had "very, very little impact."

"The catastrophic situation in Gaza is the worst since the war began," he said.

Meanwhile, despite his frustration, Hijazi said he will try again on Sunday.

"People are ready to eat each other to provide for their families," he said, adding that the new system is moving people around like chess pieces. "It is an unimaginable tragedy."