Outside a warehouse in southern Gaza one day this week, a small crowd of men and boys waited their turn for a bit of the humanitarian aid that Gaza — sick, starving, freezing Gaza — has desperately needed. They walked away with sacks of flour and cardboard boxes of food, many dragging their precious cargo behind them in two-wheeled shopping carts.

It was an orderly sight that had become rare in the territory since the war began more than 15 months ago. Israeli restrictions on aid, a security collapse that allowed widespread looting of aid trucks and other obstacles had combined to limit the food, water, tents, medicine and fuel that reached civilians amid an Israeli siege on the strip.

In the week since a cease-fire agreement stopped the fighting in Gaza, Palestinians in Gaza and aid officials say that more food deliveries and other much-needed items are streaming in. The question now is how to maintain the level of aid they say Gaza needs, despite many logistical challenges and uncertainties over how long the truce will hold.

The United Nations moved as much food into Gaza in three days this week as it did in the entire month of October, the interim head of the U.N. humanitarian office for Gaza, Jonathan Whittall, said in a briefing on Thursday.

Other U.N. agencies and aid groups were distributing medical supplies and fuel to power hospitals and water wells, among other types of assistance, and helping to repair critical infrastructure. Tents were set to enter soon, and bakeries were expected to start supplying bread by Friday, according to the United Nations.

Since the start of the cease-fire, civilian police officers belonging to the Hamas government have re-emerged, which appears to have restored some security and order to the enclave. The show of Hamas control, however, may complicate prospects for a durable peace in Gaza.

COGAT, the Israeli government agency that oversees policy in Gaza and the West Bank, did not respond to a request for comment, but it said in a post on social media on Friday that 4,200 aid trucks had entered the Gaza Strip over the past week after being inspected.

Throughout the war, Israel said that it was not limiting aid into Gaza and blamed humanitarian agencies for failing to distribute the supplies it admitted into the enclave after screening.

In all, anywhere between about 600 and 900 truckloads of aid have arrived in Gaza each day since the cease-fire took effect on Jan. 19, dwarfing the few dozen trucks that had been entering daily in recent months.

By Tuesday, Kholoud al-Shanna, 43, and her family had received a bag of flour from the World Food Program, the first in two months.

It was welcome. But “we’re still missing the basics,” Ms. al-Shanna said. “My kids haven’t had fresh vegetables in so long that they’ve almost forgotten what they taste like. How are we supposed to survive on just flour?”

Improvements were coming on that front, too. Before the war, Gaza was supplied with a mix of donated aid and goods for sale. Small amounts of imported fresh produce, meat and other food continued to be sold in markets until Israel banned most commercial items late last year, arguing that Hamas was profiting off the trade. Some commercial goods have entered Gaza this week, according to aid workers, bringing fresh vegetables and even chocolate bars to markets at lower prices than shoppers have seen in many months.

Distributing the aid once it enters Gaza remains a work in progress. Many roads are in ruins after 15 months of war, though Gaza municipalities are starting to clear debris. Unexploded ordnance still litters the enclave, making distribution and repairs dangerous.

About 500 trucks carrying a mix of aid and commercial goods entered Gaza each day before the war. The cease-fire agreement envisions 600 trucks entering each day, which aid officials say they will be hard-pressed to sustain on their own. .

“It cannot be delivered just by the United Nations, no way,” Philippe Lazzarini, the head of the United Nations Relief and Works Agency, or UNRWA, the primary lifeline for Palestinian refugees, said days before the cease-fire took effect.

UNRWA’s precarious situation is another potential hindrance: While U.N. officials say the agency is crucial to the aid effort because it forms the backbone of supply chains and services in Gaza, Israel has moved to ban the agency over accusations that it shielded Hamas militants. Aid officials say there is nothing comparable to take its place.

The biggest challenge of all is the sheer scale of the emergency. Though aid may be rolling in now, aid officials said, Gaza has been so lacking in assistance that it will take a deluge of supplies just to stabilize the population and prevent more deaths, to say nothing of eventual reconstruction.

Gaza will also need educational and psychological services and other support to begin to recover, officials say.

The number of trucks recently entering Gaza “is still a drop in the ocean compared to the amount of aid needed to catch up on what has been a massive dearth over the last year and a half,” said Bob Kitchen, the vice president for emergencies at the International Rescue Committee.

Some obstacles are gradually yielding. Israel’s evident willingness to usher in a surge of aid has resolved what aid officials and governments that donated assistance say was the biggest hurdle to getting Gaza what it needed. Saying its goal was to keep Hamas from resupplying through aid shipments, Israel had imposed stringent inspections on the assistance entering Gaza and restricted its movement once inside Gaza, frequently delaying or outright stopping delivery.

Aid workers no longer need to ask permission from the Israeli military to move around Gaza, except from south to north, speeding up the process. Before the cease-fire, many trucks designated to ferry aid to warehouses around the strip sat paralyzed for lack of fuel; now fuel is entering.

Israel still prohibits agencies from bringing in a long list of items that aid officials say are vital to the emergency response but that Israel deems “dual use,” meaning they could also be used by Hamas for military purposes. That has included everything from scissors to tent materials.

Some of those restrictions have been lifted, however, aid officials say, and talks are continuing about lifting more.

Another problem plaguing aid distribution in Gaza for months was looting, which diverted much of the aid meant for civilians.

The situation in Gaza deteriorated after the Israeli military invaded Rafah, in southern Gaza, in May, seeking to oust Hamas from what Israel said was one of its final strongholds. Hamas’s security forces fled, and organized gangs — with no one stopping them — began intercepting aid trucks after they crossed into Gaza.

International aid workers accused Israel of ignoring the problem and allowing looters to act with impunity. The United Nations does not allow Israeli soldiers to protect aid convoys, fearing that would compromise its neutrality, and its officials called on Israel to allow the Gaza police, which are under Hamas’s authority, to secure their convoys.

Israel, which has sought to destroy Hamas in Gaza, accused it of stealing aid and said the police were part of its apparatus. In the end, security broke down so badly that many aid groups kept their deliveries sitting at Gaza’s borders rather than risk the dangerous drive into Gaza.

But fears that organized looting would continue after the cease-fire have eased. Policemen are once again patrolling much of Gaza. While some people are still pulling boxes from trucks — scenes described by aid officials and witnessed by a New York Times reporter — it is now on a far smaller scale.

Palestinians in Gaza say that as aid becomes more widely available, people will have less incentive to loot.

“I’ve noticed a clear improvement — more people are getting food parcels today,” said Rami Abu Sharkh, 44, an accountant from Gaza City who had been displaced to southern Gaza. “I hope it continues until theft is eliminated completely.”

Farnaz Fassihi contributed reporting from New York.