The United Nations rights chief described Wednesday Israel's threat to suspend dozens of aid groups from operating in Gaza from January as "outrageous", calling on states to urgently insist Israel shift course.
"Israel's suspension of numerous aid agencies from Gaza is outrageous," Volker Turk said in a statement.
"Such arbitrary suspensions make an already intolerable situation even worse for the people of Gaza," he warned.
His comment came after Israel said that 37 aid organisations will be banned from operating in Gaza starting on Thursday, unless they comply with its new guidelines requiring detailed information on Palestinian staff.
Israel has singled out international medical charity Doctors Without Borders (MSF), alleging that it had two employees who were members of Palestinian militant groups Islamic Jihad and Hamas.
Apart from MSF, some of the 37 NGOs to be hit with the ban are Norwegian Refugee Council, World Vision International, CARE and Oxfam, according to the list given by Zwick.
Several NGOs have told AFP the new rules will have a major impact on aid distribution in Gaza, with humanitarian organisations saying the amount of aid entering the region remains inadequate.
MSF told AFP in a statement that "We call on the Israeli authorities to ensure that MSF and other INGOs (international non-governmental organisations) are registered in Israel to continue working in the West Bank and Gaza in 2026."
"We continue to seek reassurances and clarity over a concerning request to share a staff list, which may be in violation of Israel's obligations under international humanitarian law and of our humanitarian principles," the charity said.
"We will be exploring all possible avenues to alter the outcomes of this decision."
"This is the latest in a pattern of unlawful restrictions on humanitarian access," Turk said, pointing to Israel's ban on the UN agency supporting Palestinian refugees, UNRWA, and "attacks on Israeli and Palestinian NGOs amid broader access issues faced by the UN and other humanitarians".
"I urge all States, in particular those with influence, to take urgent steps and insist that Israel immediately allows aid to get into Gaza unhindered," he said.
The UN High Commissioner for Human Rights said he wanted to "remind the Israeli authorities of their obligation under international law to ensure the essential supplies of daily life in Gaza".
This, he stressed, includes "allowing and facilitating humanitarian relief".
Philippe Lazzarini, the head of UNRWA, said in a post on X that the move was "a dangerous precedent."
He added that "failing to push back against attempts to control the work of aid organisations will further undermine the basic humanitarian principles of neutrality, independence, impartiality and humanity underpinning aid work across the world"