Israeli forces pounded central Gaza by land, sea and air on Wednesday and Palestinian authorities reported dozens more deaths in the 11-week-old conflict after Israel's military chief said the war on Hamas would grind on for months.

Reflecting Israeli resolve to wipe out Hamas despite growing international calls for a ceasefire, Israel's Chief of Staff Herzi Halevi said the fighting would last "many months" and there were no "magic solutions" or "shortcuts".

The Gaza health ministry said Israeli forces had killed 195 Palestinians and wounded 325 in the past 24 hours, bringing the recorded toll to 21,110 killed and 55,243 wounded in Israeli attacks in the coastal territory since October 7.

A telecommunications outage in much of the enclave hit efforts to reach Palestinian casualties overnight but was gradually coming back online at mid-morning.

In central Gaza's Al-Maghazi district, five Palestinians were killed in one air strike, medics said, while to the north in Gaza City health officials said the bodies of seven Palestinians killed overnight arrived at Al Shifa Hospital.

Residents also reported heavy fighting east and north of Al-Bureij district and in the nearby village of Juhr Ad-Deek, where they said Israeli tanks are stationed.

Israel's military on Wednesday reported three more soldiers killed in action in Gaza, bringing total military losses in the enclave since ground operations began on October 20 to 166.

The Hamas armed wing said its fighters attacked four Israeli bulldozers and a tank in the northern part of Khan Younis, the main city in southern Gaza and the scene of heavy fighting for several days.

Israel intensified its raids this week, particularly in a central area just south of the waterway that bisects the Gaza Strip. The Israeli army told civilians to leave the area, though many said there was no safe place left to go.

The World Health Organisation released footage taken mostly on Monday and Tuesday at several Gaza hospitals, with WHO emergency medical team coordinator Sean Casey saying Gaza's health capacity was 20 per cent of what it was 80 days ago.

Since Hamas killed 1,200 people and captured 240 hostages in a cross-border rampage on October 7 was the deadliest day in Israel's history, Prime Minister Benjamin Netanyahu has responded with an assault that has laid much of Hamas-ruled Gaza to waste.

Nearly all the enclave's 2.3 million people have been driven from their homes, many several times.