"It has been 12 months of unrelenting tragedy – this must end," Joyce Msuya, the acting under-secretary-general for humanitarian affairs and emergency relief coordinator, said in a statement.
"Member States must wield their influence to ensure respect for international humanitarian law and human rights and compliance with the rulings of the International Court of Justice,” Msuya added.
She also called on the member states to work to “end impunity,” adding: “An immediate ceasefire and durable peace are long overdue."
Decrying a year of “unimaginable suffering” in Gaza, she said: "No statistics or words can fully convey the extent of the physical, mental and societal devastation that has taken place."
"But we know what must happen: The hostages must be released and treated humanely. Civilians must be protected and their essential needs met. Palestinians arbitrarily detained must be released," Msuya said.
"Humanitarian workers must be safeguarded and their work facilitated. Perpetrators must be held accountable for any serious violations of international humanitarian law. And the assault on Gaza must stop," she added.
OCHA stressed that the past year has seen Israel blocking humanitarian access into and within Gaza, crippling aid operations.

"As a result, a weakened population is left to battle disease, hunger and death," it said.   
Gaza 'most dangerous place' for aid workers
The agency lamented the high death toll among aid workers in Gaza.
"More than 300 aid workers, the vast majority from the UN Relief and Works Agency for Palestine Refugees in the Near East (UNRWA), have been killed in Gaza – more than in any other single crisis, making Gaza the most dangerous place for aid workers," it said.
It noted that humanitarian agencies continue to deliver aid when and where they can despite the immense risks – including violence, looting of supplies, and access challenges.
Israel has continued its brutal offensive on the Gaza Strip following an attack by the Palestinian group Hamas on Oct. 7, 2023, despite a UN Security Council resolution calling for an immediate cease-fire.
Nearly 42,000 people have since been killed, mostly women and children, and over 97,100 others injured, according to local health authorities.
The Israeli onslaught has displaced almost the entire population of the territory amid an ongoing blockade that has led to severe shortages of food, clean water, and medicine.
Mediation efforts led by the US, Egypt, and Qatar to reach a Gaza cease-fire and prisoner swap agreement between Israel and Hamas have failed over Israeli Prime Minister Benjamin Netanyahu’s refusal to halt the war.
Israel faces a genocide case at the International Court of Justice for its actions in Gaza.