Centrist member of Israel's three-member war cabinet, Benny Ganz, threatened to resign if the government does not adopt his six-point plan for the Gaza operation by 8 June.
The announcement deepens a divide within Israel's leadership more than seven months into a war in which Israel is yet to accomplish its stated goals of dismantling Hamas and returning hostages abducted in the militant group's 7 October attack.
Gantz spelled out a six-point plan that includes the return of the hostages, ending Hamas' rule, demilitarising the Gaza Strip and establishing an international administration of civilian affairs. It also supports efforts to normalise relations with Saudi Arabia and widen military service to all Israelis.
''If you choose the path of fanatics and lead the entire nation to the abyss, we will be forced to quit the government,'' Gantz said.
His departure would leave Israeli Prime Minister Benjamin Netanyahu even more beholden to far-right allies who have taken a hard line on negotiations over a ceasefire and hostage release, and who believe Israel should occupy Gaza and rebuild Jewish settlements there.
Gantz spoke days after Israeli Defense Minister Yoav Gallant, the third member of the war cabinet, said he would not remain in his post if Israel elected to reoccupy Gaza. Gallant also called on the government to make plans for Palestinian administration of the territory.
In what will be seen by some as a veiled swipe at Netanyahu, Gantz said ''personal and political considerations have begun to penetrate into the holy of holies of Israel's security''. Netanyahu's critics accuse him of seeking to prolong the war to avoid new elections, allegations he denies.
Body of kidnapped Israeli found in Gaza: IDF
The body of an Israeli hostage who was captured by Hamas militants while on a cycling trip has been recovered from Gaza, according to the Israel Defense Forces.
The Hostages and Missing Families Forum said Ron Benjamin, 53, was riding his bike in the Kibbutz Be'eri in Israel when he was kidnapped during the 7 October attack.
The Israeli military said that his body was recovered by IDF soldiers operating in Gaza.
Chief military spokesperson Rear Admiral Daniel Hagari said Ron Benjamin was found along with three other murdered hostages whose repatriation was announced on Friday.
The remains of Itzhak Gelerenter, 56, Amit Buskila, 28, and Shani Louk, 22, were discovered in an operation carried out by Israel's military and intelligence agency Shin Bet, Hagari said.
Hamas vows to confront Israel's ground invasion of Rafah
The armed wing of Hamas said Palestinians will continue to stand up to Israel's ground invasion of Rafah and other places in Gaza ''no matter how long the aggression lasts and regardless of its form'', according to Al Jazeera.
At least 630,000 people have fled Israeli attacks in southern Rafah, which borders Egypt, in the past week and a further 100,000 in Gaza's north.
It comes after the Israeli army urged Palestinians to immediately evacuate parts of the city, indicating an imminent ground invasion and prompting a response from Hamas.
The Palestinian armed group had earlier warned Israel that any military operation in Rafah in the Gaza Strip "will not be a picnic".
Hamas said in a statement that Palestinian militant groups, led by Hamas' military wing, the Qassam Brigades, ''are ready to defend our people and defeat the enemy''.
According to an Israeli Defense Forces statement, people in Rafah were told to move to Muwasi, an Israeli-declared humanitarian area near the coast. The army said it had expanded assistance into the area, including field hospitals, tents, food and water.