Medical charity Doctors Without Borders, known by its French acronym MSF, expects to be barred from operating in Gaza once it misses Wednesday’s deadline to comply with new registration rules for relief agencies that Israel claims are meant to prevent Hamas from exploiting international aid.

The organisation, which provided care to nearly half a million people during a two-year Gaza Strip war, says deregistration would cut off life-saving medical assistance for hundreds of thousands in the Palestinian enclave.

COGAT, the Israeli military agency that coordinates aid, said MSF had refused to provide Israel’s Diaspora Affairs Ministry with a list of its employees as required.

The Diaspora Affairs Ministry claims individuals affiliated with MSF have links to Hamas and Palestinian Islamic Jihad. MSF rejects the accusations as unsubstantiated.

When asked, MSF did not state if it had provided names.

In May, aid agency Oxfam said the requirement to share staff details raised protection concerns, following attacks on humanitarian workers in Gaza.

MSF told Reuters that the impact would be devastating if it is barred from operating, as the humanitarian crisis deepens.

“If MSF is prevented from working in Gaza, it will deprive hundreds of thousands of people from accessing medical care,” the group said, highlighting the stakes for civilians already struggling to access health services.

Dozens of other international aid groups are at risk of deregistration, potentially forcing closures or restrictions on operating in Gaza and the occupied West Bank, within 60 days, if they did not comply by December 31 with new criteria set by Israeli authorities.

While some international aid groups have been registered under the system that was introduced in March, the Norwegian Refugee Council and Oxfam told Reuters they too are preparing for possible deregistration.

If that happened, the NRC said it would likely be forced to shutter its East Jerusalem office and will not be able to bring foreign aid workers into Gaza. It has around 200 local staff as well as 35 international staff across Gaza and the occupied West Bank, including East Jerusalem.

“At a time when needs in Gaza far exceed the available aid and services, Israel has and will continue to block life-saving aid from entering,” Shaina Low, spokesperson for the NRC, said.

Oxfam’s Policy Lead in the Occupied Palestinian Territory Bushra Khalidi told Reuters that its Palestinian staff and partners would continue supporting communities but said forcing aid agencies to rely on obtaining supplies locally — as they will not be permitted to bring in goods from outside — was part of a wider dismantling of the humanitarian aid system.

On Tuesday, the British Foreign Office published a statement alongside France, Canada and others saying Israel should allow NGOs to work in Israel in a sustained and predictable way, and shared concern about the humanitarian situation in Gaza.

COGAT said 4,200 aid trucks will continue to enter every week via the UN, donor countries, the private sector, and more than 20 international organisations that have been reregistered.