The UN humanitarian coordinator for Gaza said Tuesday that 1.9 million people were now displaced in the territory, adding she was "deeply concerned" by reports of new evacuation orders for Khan Yunis.

The United Nations has estimated that up to 250,000 people are impacted by the Israeli military order for civilians to leave Al-Qarara, Bani Suhaila and other localities near the territory's second city of Khan Yunis.

"Over 1 million people have been displaced once again, desperately seeking shelter and safety (and) 1.9 million people are now displaced across Gaza... I'm deeply concerned about reports of new evacuation orders issued in the area of Khan Yunis," Sigrid Kaag told the UN Security Council.

"Palestinian civilians in Gaza have been plunged into an abyss of suffering. Their homes life shattered, their lives upended. The war has not merely created the most profound of humanitarian crises. It has unleashed a maelstrom of human misery," Kaag added.

She said that not enough aid was reaching the war-torn strip, and that the opening of new crossings, particularly to southern Gaza, was necessary to avert a humanitarian disaster.

Kaag said the Rafah crossing between Gaza and Egypt should be re-opened, and also pleaded with the international community to do more to fund relief efforts.

The war started after Hamas's October 7 attack on southern Israel resulted in the deaths of 1,195 people, mostly civilians, according to an AFP tally based on Israeli figures.

The militants also seized 251 hostages, 116 of whom remain in Gaza, including 42 the army says are dead.

Israel's retaliatory offensive has killed at least 37,925 people, also mostly civilians, according to data from the health ministry in the Hamas-run territory.

Israel has not specifically said there will be a military operation in southern Gaza, but so far nearly every evacuation order has heralded major battles.