It renews calls on the Israelis and the Palestinians "to conduct investigations that are independent, credible and in conformity with international standards."
In the wake of the 22-day Israeli onslaught on Gaza launched in late December 2008, a UN inquiry panel accused both Israel and the Islamist movement Hamas of war crimes and possible crimes against humanity.
Some 1,400 Palestinians and 13 Israelis were killed during the Israeli military blitz in response to unrelenting rocket-fire into Israel from the impoverished Hamas-ruled Gaza Strip.
Friday's resolution asks UN chief Ban Ki-moon to report back to the assembly "within a period of five months on the implementation of the present resolution."
In the light of Ban's next report, any "further action, if necessary, by the relevant UN organs and bodies, including the Security Council" could be taken.
Riyad Mansour, the Palestinian observer to the UN, who drafted the text expressed gratitude for the "overwhelming vote in favor of fighting against impunity and demanding accountability."
Israel's UN Ambassador Gabriela Shalev told the assembly that her country "is conducting and will continue to conduct investigations that are independent, credible and in conformity with international standards."
But she also reasserted Israel's right to self-defense.
"Israel will never neglect its duty to defend its citizens, its existence, its democracy and its freedom," she noted. "We remain committed to acting in accordance with international law and the law of armed conflict."
Israel and the United States were among the seven members who voted against the resolution, along with Canada, Micronesia, Nauru, Panama and the former Yugoslav Republic of Macedonia.
But China and many European delegations, including Britain and France, voted in favor. Germany and Russia abstained.
The deputy US ambassador to the UN, Alejandro Wolff, reiterated Washington's view that the UN panel report by South African judge Richard Goldstone "is deeply flawed."
He cited among other things "its unbalanced focus on Israel, the negative inferences it draws about Israel’s intentions and actions."
Last year, Goldstone recommended that both sides face possible prosecution before the International Criminal Court in The Hague if they failed to conduct credible, independent investigations within six months.
In November, the General Assembly overwhelmingly passed a similar resolution calling for credible, independent investigations of the war crime charges by February 5, with 114 voting in favor, 18 against, and 44 abstaining.
Israel has denied violating international law, but in its report into the allegations admitted "tragic results" due to the "complexity and scale" of conducting a military operation in a heavily populated area.
It also noted that two Israeli senior officers -- a brigadier general and a colonel -- had been disciplined for firing of white phosphorus shells toward a UN compound.
A similar report from the Palestinian side said a commission of five well-known judges and legal experts had been set up to look into allegations of war crimes on its side during the conflict.
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