Peter Maurer, the head of the International Committee of the Red Cross (ICRC), on Thursday warned of a "crisis of hope" in Gaza, calling the humanitarian situation in the enclave "dire".

Speaking at the end of a three-day trip to the region, Maurer warned that conditions in Gaza were worsening by the day, with the two million residents getting only three or four hours of mains electricity a day.

He added that the power shortage had led to a water and sewage crisis, which in turn is having serious effects on the health system.

"While we can always argue on who did take what decision for what reason, the humanitarian consequences for the people of Gaza are dire and are really unacceptable," he said in English at a press conference in Jerusalem, according to AFP.

He said a "crisis of hope" in Gaza, and among Palestinian Arabs generally, was "the most lasting impression that I take away" from the trip.

Palestinian Authority (PA) chairman Mahmoud Abbas has been trying in recent months to pressure Gaza's Hamas rulers to return control of Gaza to his Fatah movement, most notably by cutting electricity supplies to Gaza through Israel.

Egypt delivered a million liters of fuel to the Gaza power station in late June, but power supplies took a fresh hit shortly thereafter, as Hamas accused the PA of blocking fuel payments to Egypt from going through banks.

In late August, the UN released $2.5 million from a pooled humanitarian fund to cover urgent needs in Gaza, as it continues to deal with electricity shortages.

During his visit to the region, Maurer met with the Gaza head of Hamas, Yahya Sinwar, and asked that he be allowed to visit "the Israeli soldiers missing in Gaza."

Hamas has held the bodies of Oron Shaul and Hadar Goldin since the soldiers fell during Operation Protective Edge in 2014. Hamas also holds several Israeli civilians captive, including Avera Mengistu and Hisham Shaaban al-Sayed.

Maurer was not permitted to visit the captives.

The ICRC chief also met with Prime Minister Binyamin Netanyahu, who asked Maurer to assist in the efforts to bring back the missing Israelis.

The Red Cross has in the past urged Hamas to comply with its obligations under international humanitarian law and provide an update on the condition of Israeli nationals who went missing in Gaza.

Hamas not responded to the request.

AFP contributed to this report.