In a joint statement they urged United Nations member states to stop sending weapons, parts and ammunition to "stop the crisis in Gaza and avert further humanitarian catastrophe and loss of civilian life.

"Israel's bombardment and siege are depriving the civilian population of the basics to survive and rendering Gaza uninhabitable," the statement added.

"The civilian population in Gaza faces a humanitarian crisis of unprecedented severity and scale."

Following Hamas's October 7 attack on Israel "armed groups in Gaza have continued to indiscriminately fire rockets toward population centres in Israel", the statement added.

Around 1,140 people were killed in the attacks on southern Israel and some 250 taken hostage, 132 of whom are still being held. The number includes at least 28 hostages now known to be dead.

In response, Israel has carried out a relentless offensive that has killed at least 25,700 people in Gaza, according to the health ministry in the Hamas-run territory.

The war has led to dire shortages of food, water, fuel and medicines in the besieged territory.

The 16 signatories include Amnesty International, Christian Aid, Medecins du Monde International Network, Norwegian People's Aid, Oxfam and Save the Children.

They call for all transfers of arms to be stopped immediately while there was a risk "they are used to commit or facilitate serious violations of international humanitarian or human rights law.

"Hostage-taking and indiscriminate attacks are violations of international humanitarian law and must end immediately," it added.

According to the organisations, Israeli military activity has destroyed a "substantial portion of Gaza's homes, schools, hospitals, water infrastructure, shelters, and refugee camps".

Not a single medical facility in Gaza was fully operational and those still able to function had been overwhelmed with trauma cases and shortages of both doctors and medical supplies, the statement added.