The UN special rapporteur on health rights on Wednesday called for an independent investigation into the bombing of Gaza's only power station.
"The destruction of Gaza's electricity power station is profoundly inconsistent with the health and safety of all civilians living in Gaza, especially the young, sick, infirm and elderly," Paul Hunt said.
"Moreover the destruction of Gaza's electricity power station may be a violation of international humanitarian law," he added.
The power station was knocked out during the night of June 27, just days after the capture of the Israeli soldier Corporal Gilad Shalit, which triggered the military incursion by Israel into Gaza.
The loss of power had knocked out water pumps affecting supplies and sewage for tens of thousands of households throughout the Gaza Strip. The lack of water had led to a spiral of ill health with reported cases of diarrhea up by 163 percent on the same period last year. It was possible other communicable diseases such as cholera would re-emerge.
It was important, Hunt said, that the widening conflict in Lebanon did not deflect attention away from the deepening humanitarian crisis in the Gaza Strip.
Since the offensive began last month, more than 100 Palestinians had been killed, including 18 children. Four hundred had been injured, 108 of them children according to UN sources.
The Israeli blockade of Gaza's borders meant medical patients returning from treatment abroad had been stranded at the Rafah crossing, while nine Palestinians waiting there had died.
Poverty rates in the region had now risen to 75 percent.
However it was the attack on the power station that was depriving civilians of the "highest attainable standard of health," which was enshrined in the International Bill of Rights.
"The basic rule of international humanitarian law is that parties to a conflict must always distinguish between combatants and civilians," Hunt said.