More than 100 organisations have signed a joint letter calling on Israel to stop the "weaponisation of aid" into Gaza, as "starvation deepens".
Humanitarian groups, including Oxfam and Médecins Sans Frontières (MSF), say they are increasingly being told they are "not authorised" to deliver aid, unless they comply with the stricter Israeli regulations.
Groups risk being banned if they "delegitimise" the state of Israel or do not provide detailed information about Palestinian staff.
Israel denies there are restrictions on aid and says the rules, introduced in March, ensure relief work is carried out in line with Israel's "national interests".
According to the joint letter, most major international non-governmental organisations (NGO) have been unable to deliver a single truck of lifesaving supplies since 2 March.
