Hundreds of thousands of people will have to decide whether to risk staying put or fleeing south to overcrowded areas, many of which are in ruins, as Israel looks set to launch a full invasion of the city.

The Israeli military has urged a full evacuation of Gaza City ahead of its planned expanded military operation in the city in northern Gaza.

Israel's military on Tuesday ordered Gaza City residents to evacuate ahead of a new offensive to seize the enclave's largest urban centre, part of a planned takeover stirring international alarm over the fate of the entire territory.