The UN World Food Program says funding shortages are forcing major cuts to its aid program in Gaza, leaving about 500,000 people without monthly food support in a territory where two-thirds of the population struggle to get enough to eat.
The WFP said it was reducing the number of recipients of its monthly assistance to 1.1 million people from 1.6 million.
In addition, food rations have been halved, cash assistance has been cut for 75,000 families, and the number of daily hot meals for those unable to cook has fallen to 150,000 from 250,000, with some families in hard-to-reach areas now receiving a hot meal only every other day.
The WFP said about 1.4 million people, or two-thirds of Gaza's population, face crisis levels of food insecurity or worse, including roughly 200,000 people in emergency conditions.
Last year's US-brokered Gaza ceasefire calls for the eventual reconstruction of the territory. But little progress has been made towards implementing a deal to end the conflict that includes terms for Hamas to disarm and Israel to withdraw its troops.
"It's a year into the agreement of this ceasefire. Well, life is still brutal here. There is no proper shelter. There is no basic services. There is no safety, no security," WFP executive director Carl Skau told Reuters in Gaza.
"These cuts are happening just as we are facing the fourth winter. You know, I've been through the winters here, absolutely brutal."
The WFP said it urgently needed $US450 million ($A646 million) over the next six months to maintain critical operations in Gaza and the Israeli-occupied West Bank.
"We tell the world now is this is not the time to look away. This is the time to step up to sustain this support, to protect the progress that has been made, but also to push for early recovery," said Skau.