"We receive fuel usually on a daily basis, but since last week we have received very little fuel," Rafiq Maliha, director of the Gaza power station company, told Al Jazeera.
"If the fuel supply is not resumed as usual we have to shut down the power plant in a couple of days.
An Israeli official said on Sunday that the fuel terminal at the crossing would remain closed for at least several more days.
"The terminal will remain closed for a few days to give us time to check and decide on measures to ensure security," Tzahi Hanegbi, the head of parliament's foreign affairs and defence committee, told Israeli military radio.
He said that "no strategic decision has been taken" to close the crossing indefinitely.
Two Israeli employees at the facility were killed when it was stormed by Palestinian fighters.Breaking the siege
Hamas, which has controlled Gaza since pushing out security forces loyal to the Palestinian president last year, said that attack was the start of a push to break the Israeli blockade of the territory.
Israel normally supplies 60 per cent of the electricity for Gaza's 1.5 million inhabitants
Gaza needs around 240MW of electricity, but normally receives only about 200MW, with 8 per cent from Egypt
Israel is the only source of industrial fuel for Gaza's power station
Israel first stopped supplying industrial fuel supplies to Gaza on January 19
The EU pays Israel around $10m per month for Gaza's industrial fuel
"There has been a decision on the part of the Palestinian people and the Hamas movement and the national unity government to break the siege on the Gaza Strip," Fawzi Barhoum, the group's spokesman, told the AFP news agency.
"There are options for the resistance to address this issue with the Israeli occupation, and they must continue.
"I consider the recent Nahal Oz operation to be the beginning of these options."
Israel has sealed the densely populated coastal strip off from all but vital humanitarian supplies since Hamas took full control.
The power plant previously stopped operating in January after Israel halted supplies, causing blackouts and shutting vital water treatment facilities.'Artificial crisis'
Zeev Boim, Israel's housing minister, said: "It is outrageous for Hamas to carry out a terror attack and kill people who operate the fuel terminal and to later claim that there is a humanitarian crisis.
"It is trying to create an artificial crisis in the eyes of the international community at the expense of hundreds of thousands of suffering Gaza residents."
Meanwhile, at least two members of Hamas' armed wing were killed on Sunday in an explosion in a house in the town of Jabaliya in the northern Gaza Strip, according to Palestinian medics.
The cause of the explosion was not yet clear but an Israeli army spokeswoman said there had been no Israeli military activity in the area.
Also on Sunday, four people were wounded in the West Bank city of Nablus when a governor came under attack in the Balata refugee camp, witnesses and securioty officials said.
Jamal Muhaisen took cover in a house within the camp and was later evacuated by Palestinian police.
Palestinian security officers couldn't say who was responsible for the attack.