A first-of-its kind gathering of Catholic leaders called on Pope Francis to consider writing an encyclical letter, or some other "major teaching document," reorienting the church's teachings on violence after they issued a blunt rejection of the Catholic church's long-held teachings on just war theory.

The call was made on Thursday at the end of a three-day conference in the Vatican.

In the conference's final appeal document, titled "An Appeal to the Catholic Church to Re-Commit to the Centrality of Gospel Nonviolence," the participants said Church teachings on war too often been used to justify violent conflicts. It said the global church must reconsider Jesus' teachings on nonviolence, the Associated Press reports.

"We need a new framework that is consistent with Gospel nonviolence," the document said, noting that Pope Francis and his past four predecessors have all spoken out against war. "We propose that the Catholic Church develop and consider shifting to a Just Peace approach based on Gospel nonviolence."

"Too often the 'just war theory' has been used to endorse rather than prevent or limit war," said the document, according to the National Catholic Reporter.

"Suggesting that a 'just war' is possible also undermines the moral imperative to develop tools and capacities for nonviolent transformation of conflict," the paper said.

The event was co-hosted by the Pontifical Council for Justice and Peace and the international Catholic peace organisation Pax Christi.

The just war theory is a Catholic tradition that uses a series of criteria to evaluate whether the use of violence can be considered morally justifiable. It was first referred to by fourth-century bishop St. Augustine of Hippo, and later articulated in depth by 13th-century theologian St. Thomas Aquinas.

The April 11-13 conference was held in Rome and attended by experts engaged in global nonviolent struggles under the aegis of the Vatican.

The conference was held after a number of theologians criticised the continued use of the theory in modern times, saying that both the powerful capabilities of modern weapons and evidence of the effectiveness of nonviolent campaigns make it outdated.

Several of the event's participants said the church should simply no longer teach the just war theory.

"I came a long distance for this conference, with a very clear mind that violence is outlived," said Archbishop John Baptist Odama of Gulu, Uganda. "It is out of date for our world of today."

"We have to sound this with a strong voice," said the archbishop. "Any war is a destruction. There is no justice in destruction. ... It is outdated."

One of the criteria for moral justification of war, according to the Catechism of the Roman Catholic Church, is that "the use of arms must not produce evils and disorders graver than the evil to be eliminated."

Odama, who also leads Uganda's Catholic bishops' conference, said the conditions in the Catechism "are only given to say in reality there should be no war."

"This is where the group was very strong," he said, referring to the conference. "We should not give now, at this moment, reasons for war. Let us block them and promote relationships of harmony, of brother and sisterhood, rather than going for war."