The planned reduction of electricity supplies awaits the Gaza Strip beginning Dec. 2.
Human rights groups have denounced Israel's policy of cutting back utilities to Gaza, calling it collective punishment.
Israel has mostly closed off Gaza since the militant Islamic Hamas overran the territory in June. Several weeks ago Israel began cutting back on fuel supplies, but planned electricity reductions were delayed by an order from Israel's attorney general, who expressed concerns about humanitarian harm.
Rights groups petitioned the high court to stop the cutbacks, and on Thursday, the state responded with a one-page document that stated that Israel "will implement a certain reduction of electricity supply to the Gaza Strip beginning Dec. 2, 2007."
The document added, "In order to allow the Palestinian regime to prepare properly for the reduction, advance warning of about one week will be given before the cut." It said the attorney general's concerns had been addressed.
At first Israeli officials said the utilities cutbacks were a way of persuading the Palestinian population to pressure Palestinian militants to stop their daily rocket barrages at southern Israel. Following an outcry over the prospect of further harming the already poverty-stricken Gaza population, Israel said the cutbacks were part of its disengagement from Gaza. Israel withdrew its troops and dismantled all Jewish settlements there in 2005.
Two groups that press for Israel to respect Palestinian human rights, Gisha and Adala, issued a statement Thursday charging that the proposed electricity cuts would "cause certain and serious harm to the health and well-being of Gaza residents." Sari Bashi, director of Gisha, said there was "no physical way to reduce electricity supplies to Gaza without forcing power outages for hospitals, clinics, water wells, sewage treatment plants and schools."
Shlomo Dror, a spokesman for the Israeli military, said there would be no such harm. "It won't be a powerful cut that will cause damage," he said. "There will only be minor cuts."
Gaza is dependent on Israel for all its fuel and about half its electricity.