The Israeli military has said it expects the conflict in Gaza to continue throughout 2024.
In a new year's message, Israel Defence Forces spokesman Daniel Hagari said troop deployments were being adjusted to prepare for "prolonged fighting".
He said some troops - especially reservists - would be withdrawn to allow them to regroup.
"These adaptations are intended to ensure the planning and preparation for continuing the war in 2024," he said.
"The IDF must plan ahead out of an understanding that there will be additional missions and the fighting will continue the rest of the year."
He said that some reservists would leave Gaza "as soon as this week" to allow them to "re-energise ahead of the coming operations".
More than 21,800 people have been killed in Gaza - mostly children and women - during 11 weeks of fighting, according to the Hamas-run health ministry.
The latest war was triggered by an unprecedented cross-border attack by Hamas gunmen on southern Israel on 7 October, in which 1,200 people were killed - most of them civilians - and about 240 others taken hostage.
Israel continued its bombardment of Gaza up until the end of what has been dark year in the region.
At least 48 Palestinians were killed in overnight bombing in Gaza City on Sunday, the health ministry in Gaza said, with many still buried under the rubble.
Another strike killed 20 people sheltering at Al-Aqsa University in the west of Gaza City, witnesses told the AFP news agency. The OceanNewsUK has not been able to verify the latest reports.
The UN says 85% of Gaza's 2.4 million people - almost 2 million people - have now been displaced.
"Tonight the sky in world countries will be lit by firecrackers, and joyful laughs will fill the air.
"In Gaza our skies are now filled with Israeli missiles and tank shells that land on innocent, homeless civilians," Zainab Khalil, 57, a resident from northern Gaza now in Rafah, told Reuters.
Mr Netanyahu said on Saturday that "the war is at its height".
"We are fighting on all of the fronts," he said. "We have huge success but we also have painful cases. Achieving victory will require time.
"As the (Israeli Army) chief of staff has said, the war will continue for many more months."
Earlier on Sunday, more Israeli attacks were reported in central Gaza, with reports of air strikes in al-Maghazi and al-Bureij. On Sunday morning, the Hamas-run health ministry said 150 people had been killed in the past day.
Israel's far-right finance minister Bezalel Smotrich called for Palestinians to leave Gaza and make way for Israelis who could "make the desert bloom".
The official line from the Israeli government is that Gazans will eventually be able to return to their homes, though it has yet to outline how or when this will be possible.
Air raid sirens sounded in Tel Aviv and southern Israel as it saw in the new year, with Israeli missile defence systems intercepting rockets fired from Gaza, AFP reported.
One man who was in Tel Aviv celebrating the new year with friends said: "I was terrified, like it was the first time I saw missiles, it's terrifying."
Hamas's military wing, the Ezzedine al-Qassam Brigades, claimed responsibility for both attacks in a video posted on social media.
They said they used M90 rockets in "response to the massacres of civilians" perpetrated by Israel.
