The 575-page report, compiled by Richard Goldstone, a South African judge, concluded that there was "strong evidence" Israel had committed war crimes during its bombing and shelling of Gaza.
The Palestinian Hamas-run government in Gaza was also accused of war crimes during the conflict that left about 1,400 Palestinians and 13 Israelis dead.
Hamas said it had prepared a 52-page response to the Goldstone report, which had accused the Palestinian fighters of targeting Israeli civilians by firing hundreds of rockets across the de-facto border.
Salah al-Bardaweel, a senior Hamas official, hinted at the content of the report on Thursday.
"The killing of three Israeli civilians as alleged by Israel and as mentioned in the Goldstone report was by mistake and the target was military installations inside the Zionist cities", al-Bardaweel said.
"Resistance fighters were warned against hitting civilians."
The UN General Assembly in a November 5 resolution endorsed the Goldstone report and gave Israel and the Palestinians three months to undertake "independent, credible investigations" into the allegations against them.
That deadline expires on Friday, February 5.
But Ban Ki-moon, the UN secretary general, had asked both sides to report to him on the progress made so far so as to enable him to report back to the General Assembly before the February deadline.
With next week's deadline nearing, Israel is still in the midst of a heated debate as to whether it should heed the General Assembly resolution calling for an independent inquiry.
So far it has had its own military investigate the incidents raised in the Goldstone report, but has not established a probe independent of the army.
Barak and army chief of staff have so far opposed a commission that would expose private soldiers to legal prosecution, because they fear that would compromise combat in the future.
According to the officials quoted in the Yediot Ahronoth newspaper, only higher-ranking officers with the rank of brigadier-general and up, as well as political leaders including former premier Ehud Olmert, would have to appear before the commission being considered by Benjamin Netanyahu, the Israeli PM.
One government official told Yediot that Israel had "no choice" but to form such a commission if it wanted to escape prosecution at the International Criminal Court in The Hague.