Rome's chief Jewish rabbi on Thursday sharply criticised Pope Francis over the pontiff's recent ramping up of criticism against Israel's military campaign in Gaza, in an unusually forceful speech during an annual Catholic-Jewish dialogue event.

Francis has unfairly focused his attention on Israel compared to other ongoing world conflicts, including those in Sudan, Yemen, Syria and Ethiopia, said Rabbi Riccardo Di Segni, spiritual leader of Rome's Jewish community since 2001.

"Selective indignation … weakens the pope's strength," said Di Segni.

"A pope cannot divide the world into children and stepchildren and must denounce the sufferings of all," he said. "This is exactly what the Pope does not do."

Francis, leader of the 1.4-billion-member Roman Catholic Church, has recently been more outspoken about Israel's military campaign against Palestinian militant group Hamas. Last week, he called the humanitarian situation in Gaza "very serious and shameful".

A complex ceasefire accord between Israel and Hamas emerged on Wednesday, and is scheduled to start on Sunday.

Relations between the Catholic Church and Judaism have improved in recent decades, after centuries of animosity. The event on Thursday, held at a Catholic university, was organised to mark the 36th annual World Day of Catholic-Jewish Dialogue.

One of the organizers, Rev. Marco Gnavi, a Catholic priest, expressed surprise at Di Segni's comments.

He said he felt "discomfort" because of the rabbi's words. "You can't ask us not to suffer both with you and with others," said the priest.