Qatari-bought fuel arrived at the Gaza Strip's only power station after entering through Israel on Tuesday in a bid to alleviate conditions in the Palestinian enclave, a Hamas spokesman and sources said.

The delivery could help ease months of protests and clashes along the border between Israel and Hamas-run Gaza, which has been under a crippling Israeli blockade for more than a decade.

UN officials and Egypt have in recent weeks pursued indirect talks between Hamas and Israel.

Israeli officials however refused comment on the delivery.

A spokesman for the UN Secretary General hailed Qatar's $60mn donation for the fuel, which is expected to be spent over several months.

"Additional fuel for the Gaza power plant remains the fastest and most immediate way to increase electricity and help alleviate the humanitarian and related public health needs on the ground," Stephane Dujarric said at a briefing in New York.

He said two trucks carrying 70,000 litres of fuel had entered, while deliveries were set to increase to 15 trucks daily in the coming days.

A Palestinian source at the Kerem Shalom crossing in southern Gaza — the only goods crossing between the Gaza Strip and Israel — earlier put the number at six trucks and a far higher number of litres.

AFP journalists saw at least one truck arriving at the power station in Gaza City.

"The Qatari fuel to the Gaza Strip's power plant today is aimed at partially improving electricity (supply) in Gaza," Hamas spokesman Hazem Qassem said.

For months Gaza residents have been receiving only four hours of mains electricity a day on average.

The United Nations has warned that Israel's 11-year blockade of the enclave has resulted in a "catastrophic" humanitarian situation.

A Qatari official said the supply of fuel was intended to "to avert an escalation in the existing humanitarian disaster from becoming worse."

"There are no political motives behind this step," the official added.

"It is important to note that this operation is taking place through the United Nations which is authorised to seek the necessary permissions."