The Knights of Malta, a Catholic chivalric order and global charity, elected a new, interim leader organisation after its recent row with the Vatican.

The previous grand master, Briton Matthew Festing, resigned in January after a month-long, highly public spat with the Vatican over the running of the group, which laid bare tensions between a reformist Pope Francis and his conservative critics.

In a secret ballot, 56 electors appointed Italian Giacomo Dalla Torre as Lieutenant of the Grand Master, giving him just a one-year mandate while reforms are carried out.

"Pope Francis has been informed by letter of the election result," the Knights said in a statement.

The Vatican appointed a special delegate to run the Rome-based body following Festing's departure and had pushed, behind the scenes, for the appointment of a compromise, interim leader.

Reformers, backed by the Vatican, want to re-vamp the order's constitution to make its government more transparent and better able to respond to the massive growth it has seen in recent years. They also want to make it possible for commoners to reach top positions.

Under the current monarchical hierarchy, the top Knights are required to have noble lineage.

The organisation has a multi-million dollar budget, 13,000 members, 80,000 volunteers and 20,000 paid medical staff running refugee camps, drug treatment centres, disaster relief programmes and clinics around the world