The Israeli military said on Wednesday that it had approved the framework for a new offensive in the Gaza Strip, as Hamas condemned Israeli ground incursions in Gaza City.

The approved plan for the expanded offensive comes days after Israel's security cabinet called for the capture of the Palestinian territory's largest city following 22 months of war that have created dire humanitarian conditions.

Israeli armed forces chief Lieutenant General Eyal Zamir "approved the main framework for the IDF's operational plan in the Gaza Strip", a statement released by the army said.

Prime Minister Benjamin Netanyahu's government has not provided a precise timetable for when Israeli troops will enter Gaza City, where thousands have taken refuge after fleeing previous offensives.

Ismail Al-Thawabta, director general of the Hamas government media office in Gaza, told AFP on Wednesday that "the Israeli occupation forces continue to carry out aggressive incursions in Gaza City".

"These assaults represent a dangerous escalation aimed at imposing a new reality on the ground by force, through a scorched-earth policy and the complete destruction of civilian property," he added.

Gaza's civil defence agency has reported intensified Israeli air strikes on residential neighbourhoods of Gaza City in recent days.

Agency spokesman Mahmud Bassal told AFP that Israeli attacks had killed at least 40 people across the territory on Wednesday. (AFP)