The 193-member General Assembly adopted a resolution that also demands the release of hostages held in Gaza by Hamas, the return of Palestinian prisoners detained by Israel and the full withdrawal of Israeli forces from Gaza.
The text garnered 149 votes in favour on Thursday, while 19 countries abstained and the US, Israel and 10 others voted against.
The resolution "strongly condemns the use of starvation of civilians as a method of warfare and the unlawful denial of humanitarian access and depriving civilians ... of objects indispensable to their survival, including willfully impeding relief supply and access."
Israel's UN ambassador, Danny Danon, told the General Assembly this was "blood libel".
He had urged countries not to take part in what he said was a "farce" that undermines hostage negotiations and fails to condemn Hamas.
"It must be acknowledged that by failing to condition a ceasefire on the release of the hostages, you told every terrorist organisation that abducting civilians works," he said.
General Assembly resolutions are not binding but carry weight as a reflection of the global view on the war.
Previous demands by the body for an end to the war between Israel and Palestinian militants Hamas have been ignored.
Unlike the UN Security Council, no country has a veto in the General Assembly.
Libya's UN ambassador Taher El-Sonni told the General Assembly before the vote that for "those pressing the red button today to vote against this resolution (it) will become a blood stain on their fingers".
The US last week vetoed a draft UN Security Council resolution that also demanded an "immediate, unconditional and permanent ceasefire" and unhindered aid access in Gaza, arguing it would undermine US-led efforts to broker a ceasefire.
The other 14 member states voted in favour of the draft as a humanitarian crisis grips the enclave of more than two million people, where the UN warns famine looms and aid has only trickled in since Israel lifted an 11-week blockade in May.
The vote came before a UN conference next week that aims to reinvigorate an international push for a two-state solution between Israel and the Palestinians - a meeting the US is urging countries not to attend.
The war in Gaza has raged since 2023 after Hamas militants killed 1200 people in Israel in an October 7 attack and took some 250 hostages back to the enclave, according to Israeli tallies.
Many of those killed or captured were civilians.
Israel responded with a military campaign that has killed more than 54,000 Palestinians, according to Gaza health authorities.
