Maliha said that the shut down of three generators had "completely stopped" the Gaza Strip's infrastructure.
"Simply, if you have no electricity, you have no water, no services, no hospitals. This would be a terrible situation for the people here.
"The power plant has only been producing a 25-megawatt supply from the 140-megawatt desired capacity of the power plant."
Palestinian officials said at least 600,000 of Gaza's 1.4 million people were affected by the blackout on Friday, which brought darkness to large areas of the territory.
The Palestinian electricity company's one power plant produces three quarters of the electricty needed by the territory, but Israel supplies it with the fuel as part of past interim peace deals.
The remaining electricity needs are from the state-run Israel Electric Corporation and Egypt.
Israel's army said on Saturday that the Nahal Oz fuel crossing would reopen on Sunday for several hours.
On Friday, an Israeli military spokesman confirmed to the AFP news agency that deliveries of fuel had been stopped "for security reasons".
Almost all supplies for Gaza, including food, fuel and raw materials, come into the territory from from Israel.
Israel started to cut off supplies to Gaza after Hamas took full control in June, citing "security concerns" in opening border crossings.