Israeli leaders have been encouraged by signs of protest in Gaza against Hamas, the militant group that has controlled the enclave since 2007, and the expanded operation appears at least partly aimed at increasing civilian pressure on its leaders.
Defence Minister Israel Katz said the evacuation would take place from areas where there was fighting, while urging Gazans to eliminate Hamas and return Israeli hostages as the only way to end the war.
The Israeli military had already issued evacuation warnings to Gazans living around the southern city of Rafah and towards the city of Khan Yunis, telling them to move to the Al-Mawasi area on the shore, previously designated a humanitarian zone.
Israel's Army Radio said the 36th division, sent to the Southern Command area in March to prepare for operations in Gaza, would take part in the operation.
Israeli forces have already set up a significant buffer zone within Gaza, expanding an area that existed around the edges of the enclave before the war and adding a large security area in the so-called Netzarim corridor through the middle of Gaza.
At the same time, Israeli leaders have said they plan to facilitate voluntary departure of Palestinians from the enclave after US President Donald Trump called for it to be permanently evacuated and redeveloped as a coastal resort under US control.
Katz's remarks on Wednesday came after Israeli Prime Minister Benjamin Netanyahu repeated calls for Hamas to disarm and said the application of military pressure was the best way to get back the remaining 59 hostages.
"I call on the residents of Gaza to act now to eliminate Hamas and return all the kidnapped," Katz said in his statement, which added the operation would clear the area of militants and their infrastructure.
"This is the only way to end the war," Katz said.
Israel resumed air strikes on Gaza in March and sent ground troops back in, after two months of relative calm following the conclusion of a US-backed truce to allow the exchange of hostages held by Hamas for Palestinian prisoners in Israeli jails.
Hundreds of Palestinians have been killed since the resumption of the strikes and Israel has also cut off aid to the enclave, saying much of the material going in was taken by Hamas and used for its own members.
Efforts led by Qatari and Egyptian mediators to get back on track talks aimed at ending the war have failed to make progress.
As the operation in Gaza has escalated, Israel has also hit targets in southern Lebanon and Syria, with a strike on a Hezbollah commander in the southern suburbs of Beirut on Tuesday that added strain to the fraying ceasefire agreements that had largely halted fighting in January.
Israel invaded Gaza following the devastating attack on communities in southern Israel by thousands of Hamas-led gunmen that killed 1200 people according to Israeli tallies, and saw 251 taken as hostages into Gaza.
The Israeli campaign has killed more than 50,000 Palestinians and ravaged the Gaza Strip, forcing almost the entire population of 2.3 million from their homes.Â
