Israel and Hamas may be able to reach a Gaza ceasefire and hostage-release deal within one or two weeks but such an agreement is not likely to be secured in just a day's time, a senior Israeli official said on Wednesday.

Francesca Albanese, the United Nations' special rapporteur, has accused Israel of waging a "genocidal campaign" in Gaza.

Speaking on condition of anonymity, the official said no permanent ceasefire would be possible without the complete removal of Hamas.