The power plant is one of the main sources of electricity for Gaza's 1.8 million people and without it, daily blackouts of around 12 hours are expected. Electricity is also received directly from Israel and Egypt.
Gaza lacks much basic civil infrastructure and lives under an Egyptian-Israeli blockade meant to cut off arms flows but which also curbs imports of fuel and building supplies.
A few months ago the plant was switched off for 43 days due to a fuel shortage that arose after neighboring Egypt closed off smuggling tunnels. Israel eventually allowed in fuel paid for by Qatar when a storm swept the region.
But that fuel has run out, said Ahmed Abu Al-Amrain, a spokesman Gaza's energy authority.
The Gaza Strip is run by the Islamist group Hamas, which is sworn to Israel's destruction and the two sides have no direct dealings.
Last time there were blackouts, Qatar gave funds to Hamas's West Bank-based rival, President Mahmoud Abbas's Palestinian Authority, which then ordered fuel for the enclave from Israel.
Gaza's energy authority said on March 12 that Qatar had agreed to extend its funding of fuel for three more months.
For the arrangement to work again, Israel would have to open its commercial crossing on the border with Gaza, which it closed after violence erupted along the frontier this week.
"The closure of the crossing by the Israeli occupation is an act of collective punishment," Amrain said.