The UN Human Rights Council is yet to issue its report on the war
An Israeli government report has said that the Israeli military campaign in Gaza earlier this year was "necessary and proportionate".
The war and its conduct have been widely criticised, with Israel and Hamas accused of war crimes.
Palestinian sources say about 1,400 Gazans died in the conflict. Thirteen Israeli died.
The report said 100 inquiries had been launched into the conduct of soldiers and 14 criminal investigations opened.
According to the United Nations, the Israeli military campaign left more than 50,000 homes, 800 industrial properties and 200 schools damaged or destroyed, as well as 39 mosques and two churches.
The UN Human Rights Council has appointed former South African judge Richard Goldstone to investigate whether war crimes were committed during the conflict.
Israel has declined to co-operate, accusing the UN Human Rights Council of bias against it.
Allegations persist against the Israeli military about killings of unarmed civilians, the use of civilians as human shields and indiscriminate destruction of property.
Israeli officials insist troops went to great lengths to protect civilians, that Hamas endangered non-combatants by firing from civilian areas and that homes and buildings were destroyed only when there was a specific military need to do so.
The conflict lasted for 22 days, ending on 18 January.
"Israel had both a right and an obligation to take military action against Hamas in Gaza to stop Hamas' almost incessant rocket and mortar attacks," the report, issued on Thursday, said.
It says 12,000 rockets and mortars were fired at Israel between 2000 and 2008 - nearly 3,000 in 2008 alone.
The report explains that damage caused to UN facilities by Israeli strikes should be blamed on Hamas, which Israel says set up rocket launchers nearby.
Allegations that dozens of Palestinian civilians were killed or wounded by white phosphorus shells are dismissed.
The report detailed steps aimed at limiting civilian casualties. It says 2.5 million leaflets were dropped and 165,000 phone calls made warning civilians to leave areas that would be targeted.
It also says that humanitarian aid was allowed into Gaza throughout the conflict.
Palestinians have said it was not safe to leave their homes to try to escape fighting and shelling, that they were unable to access the humanitarian aid.