Netanyahu is now expected to hold consultations about the Gaza war with a small group of ministers, including Defence Minister Yoav Gallant and Strategic Affairs Minister Ron Dermer who had been in the war cabinet.
The prime minister had faced demands from the nationalist-religious partners in his coalition, Finance Minister Bezalel Smotrich and National Security Minister Itamar Ben-Gvir, to be included in the war cabinet, a move which would have intensified strains with international partners including the United States.
The forum was formed after Gantz joined Netanyahu in a national unity government at the start of the war in October and also included Gantz's partner Gadi Eisenkot and Aryeh Deri, head of the religious party Shas, as observers.
Gantz and Eisenkot both left the government last week, over what they said was Netanyahu's failure to form a strategy for the Gaza war.