UN humanitarians said Monday that over the weekend, they started collecting supplies that had been offloaded at the newly reopened Zikim crossing in northern Gaza.

The UN Office for the Coordination of Humanitarian Affairs (OCHA) said OCHA and its partners collected more than 5,400 tonnes of assistance between Thursday and Sunday, including food, tents, tarpaulins, blankets, mattresses, medicine and animal fodder, from all three open crossings.

On Wednesday, OCHA confirmed Israel's decision to reopen the Zikim crossing, the only functioning aid portal into the northern Gaza Strip.

OCHA said that following the heavy rains on Friday, humanitarian teams conducted rapid assessments of affected areas over the weekend and provided initial aid. More than 13,000 families are estimated to have been impacted by the flooding.

"According to our partners working on shelter, over the weekend, they helped distribute at least 9,000 tents, 83,000 tarpaulins and 59,000 blankets, with thousands more planned in the coming days," the office said. "While we and our partners have moved swiftly to respond to rain-affected areas, our efforts remain constrained by inadequate volumes of shelter and other necessary supplies allowed to enter through the UN-coordinated mechanism."

OCHA said that with temperatures dropping and winter fast approaching, humanitarians must be allowed to expand the shelter response to meet the vast scale of needs across Gaza.

The office said its partners working on food security reported that, with the volume of food parcels entering Gaza having increased in recent days, they plan to resume distributing two food parcels and one bag of flour per household across the strip.

Aid distributions in the north had to be limited earlier last week to only high-energy biscuits and one bag of flour per household because its partners working to bring supplies into the strip were facing impediments, including the de-prioritization of humanitarian cargo at crossings, customs clearance delays, and lack of access to northern crossings.