Blockade 'a catastrophe'
Bakers said they stopped production as they had neither power nor flour. Fresh loaves of pita bread are a main part of residents' diets.
Gazans said on 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.
Gaza City was plunged into darkness after the plant was shut down on Sunday, three days after the Israeli fuel blockade began.
"At least 800,000 people are now in darkness," Derar Abu Sissi, general director of the plant, said on Monday.
"The catastrophe will affect hospitals, medical clinics, water wells, houses, factories - all aspects of life."
'Ineffective and unlawful'
Gisha, an Israeli group that has fought the fuel cutbacks in Israel's supreme court, said: "Punishing Gaza's 1.5 million civilians does not stop the rocket fire - it only creates an impossible 'balance' of human suffering on both sides of the border."
Oxfam, the British charity, called the blockade "ineffective as well as unlawful."
UNRWA, the UN organisation supporting Palestinian refugees, also warned the shortages would drastically affect essential services.
"The logic of this defies basic humanitarian standards," Christopher Gunness, UNRWA spokesman, said.
The UN has also criticised Israel, saying it should not collectively punish Gaza's population while responding to security threats.
Jacky Rowland, Al Jazeera's correspondent in Gaza, said: "Doctors are now having to effectively ration the amount of healthcare that they're giving to patients."
'Patients at risk'
Dr Medhat Abbas, head of the crisis management unit at the health ministry in Gaza, said that electricity from generators would only be available for a few more hours at the Al-Nasser children's hospital.
|Palestinians fear the power cut could be |
disastrous for the health sector [AFP]
"These patients and these children are facing their destiny and they will die soon," he told Al Jazeera.
"They escaped from their poor houses where they have very cold weather ... The families brought them here to be saved in the incubator. Now the incubator and the nursery will be out of electricity.
"What sort of humanitarian law is this?"
The Israeli foreign ministry said the diversion of fuel from domestic power generators to other uses was "wholly a Hamas decision".
"Noteworthy is the fact that while the Gaza population remains in the dark, the fuel generating power to the Hamas rocket manufacturing industry continues to flow unabated," it said in a statement to Al Jazeera.
"The Hamas claim of humanitarian crisis in Gaza is also greatly exaggerated."
Israel says the blockade imposed on Gaza is in response to rockets being fired from the territory.
Zeev Boim, an Israeli cabinet minister, said that rather than condemning Israel's move, the UN should condemn Palestinian rocket attacks.
"I don't hear the UN's voice," he said.
The Strip's plant in Central Gaza, which receives its fuel from Israel and is partially supplied by the European Union, generates just under a third of the total supply.
About 70 per cent of Gaza's electricity is supplied directly from Israel and while this supply has not been interrupted, the amount supplied has been reduced in recent months.
Power outages have become commonplace in the Gaza Strip in recent months after Israel declared the area a "hostile entity" and began restricting fuel supplies.