"If we open the crossings again tomorrow there will be rockets that fall again on Israel," Dror said. "They don't want to recognize Israel and want to destroy Israel, that's their problem. They shouldn't expect that we will help them destroy us."
Dror and other Israeli officials charged that Hamas was creating a false crisis and could resume the electricity if it wanted.
Hamas claimed that five people had died at hospitals because of the power outage. However, health officials, speaking on condition of anonymity because they were contradicting the official line, denied the claim.
Israel has been trying to find a way to stop the rocket fire into its southern communities. The barrages have virtually paralyzed life there since a spike in fighting last week that followed an Israeli anti-rocket operation in Gaza.
Israel sealed all crossings into Gaza last week in response to the fighting, cutting off fuel, food and medicine.
Several weeks ago Israel reduced the fuel supply as a pressure tactic. Gazans said Monday that they were eating less meat and dairy products since they had no power for refrigerators. The price of meat has doubled in 10 days.
Late Sunday, Palestinian President Mahmoud Abbas appealed to Israel to lift the blockade, said Abbas spokesman Nabil Abu Rdeneh. Abbas effectively rules only the West Bank after Hamas expelled his forces from Gaza last June.
Abbas renewed peace talks with Israel after a US peace conference in November. On Monday, some Palestinians urged Abbas to break them off.
"We ask the Palestinian Authority to halt negotiations, and demand that (Israel) lift the embargo on Gaza as a condition of returning to negotiations," Palestinian lawmaker Mustafa Barghouti told reporters in the West Bank city of Ramallah.