The Palestinian energy authority in Gaza said on Wednesday it had paid Egypt $2 million towards fuel for its crippled power station, but had yet to receive anything in return.
Gaza is experiencing a major electricity crisis because of a shortage of fuel for its sole power plant.
The plant, which supplies nearly a third of Gaza's electricity, has shut down three times in the past month and most Palestinians are receiving only six hours of power a day.
The Palestinians have turned to Egypt for help, and recently agreed a deal which included a provision allowing them to immediately begin purchasing fuel from their Arab neighbour.
But the Palestinian Energy and Natural Resources Authority (PENRA) said it had yet to receive any fuel, despite having made a downpayment.
"$2 million was transferred to the Egyptian Petroleum Company as a downpayment for the fuel needed to operate the only power station in Gaza," PENRA said in a statement published on its website.
"So far, nothing has been received by the station, which has not been operating (fully) for weeks, increasing the suffering of the Palestinian people," it said.
PENRA hopes "the fuel enters as soon as possible so that station can resume operations."
The plant stopped generating power on March 10, for the third time in four weeks, and was operating at sharply reduced capacity on Wednesday.
On 23 February, Hamas said it had reached a "comprehensive agreement" with Egypt to end the crisis.
Under the deal, the Palestinians were to begin the immediate purchase of fuel from Egypt, with the Islamic Development Bank funding a project to upgrade and increase the capacity of Gaza's power plant by 40 megawatts.
The deal also called for the eventual connection of Gaza's electricity grid to Egypt's and for the conversion of Gaza's power plant from diesel to gas.
Gaza has long suffered outages because of shortages at its power plant, which has a maximum capacity of 140 megawatts but for some years has only been able to generate around half of that when operational.
In recent weeks, the situation has worsened because of a shortage of fuel, most of which is smuggled through cross-border tunnels from Egypt.