According to a military report, Israeli forces pounded the residential areas in the Gaza Strip with at least twenty phosphorus bombs during the offensive.
White phosphorus, classified as a 'chemical weapon' by the US intelligence, is an incendiary material that causes horrific burns, severe injuries or death when it comes in contact with skin.
According to press tv, under the Geneva Treaty of 1980, the use of white phosphorous as a weapon is prohibited.
Prior to the recent report, the Israeli army had been denying the use of the chemical against civilians despite the presence of photographic evidence to the contrary.
Human Rights Watch had warned Israel not to use white phosphorus in Gaza, saying its researchers had witnessed the use of the substance by the Israeli military in the Gaza Strip.
Meanwhile, the UN nuclear watchdog said on Wednesday that it would open an investigation into Israel's alleged use of depleted uranium during its Gaza offensive.
The UN body responded after Arab nations sent a letter to the Head of the International Atomic Energy Agency, Mohamed ElBaradei, asking for a probe into the issue.
The Israeli air, ground and naval strikes on the civilians in the besieged Gaza Strip have left at least 1,330 dead - 460 of whom were children - and 5,450 others wounded.