Michel Roy, the secretary-general, said even the smallest and materially poorest national Caritas organizations are donating what they can, for example, to help people impacted by the earthquake in Nepal April 25.

"There is a 'Francis effect' and it is going on day after day," the Caritas leader said. "It has had an effect on many people worldwide who recognize him as a real leader" and draw inspiration from his words.

"He is pushing us," Roy said.

Representatives of the 164 Caritas organizations meet in Rome every four years to set priorities, explore specific issues, approve the Caritas Internationalis budget and elect its international officers. Philippines Cardinal Luis Antonio Tagle and Maronite Archbishop Joseph Soueif of Cyprus are the two candidates for president, succeeding Honduran Cardinal Oscar Rodriguez Maradiaga.

Since the confederation was established after the Second World War, every pope has addressed the general assembly delegates at the end of the meeting. Pope Francis decided to do something different; he is scheduled to celebrate the assembly's opening Mass May 12 in St. Peter's Basilica.

"This is stronger than a meeting," Roy said. "We will hear him and that will inspire the work that we are going to be doing."

The assembly, Roy said, will have a special focus on three issues: the concrete implications of Pope Francis' call for "a Church that is poor and that is for the poor"; growing inequalities in societies and their connection to violence; and climate change and its impact on development efforts.

Dominican Father Gustavo Gutierrez, the Peruvian theologian known as the "father of liberation theology," will be one of the keynote speakers at the assembly May 12-17.

Some people, seeing Caritas engaged in social issues on behalf of the Church, make a snap judgment that the organization is "leftist," Roy said. Others, outside the Church, see Caritas upholding Catholic moral principles and values in its work and label it "conservative." Both labels are inaccurate and neither touches the heart of Caritas' motivation and activity, he said: "It is around the sanctity of life and its fullness — it's around love."

At the last general assembly, in 2011, members approved new statutes giving the Vatican more oversight of the confederation's work, and Pope Benedict XVI spoke to them about ensuring Caritas' "humanitarian and charitable activity, and the content of its documents, are completely in accord with the Apostolic See and the Church's magisterium."

Pope Francis has echoed Pope Benedict's admonitions that fidelity to the Gospel is what makes Caritas Catholic, and he has insisted the Gospel is calling the Catholic community to live differently and, especially, to treat the neediest differently. The "poor Church," Roy said, welcomes the gifts of the poor, offers them assistance, calls them to grow and contribute and listens to what they describe as their needs.

In addition to "preaching, teaching, educating and making sacraments available to everyone," he said, the Church is "invited to transform society through solidarity, through charity. Charity is a virtue that concretely transforms itself into acts of solidarity."

Being a "Church of the poor" also has strong organizational benefits, he said. The strength of the Caritas system — which even large international organizations recognize — is that Catholic charities are organized in neighbourhoods, parishes, deaneries and dioceses, meaning they know the local needs and already have an established distribution system for aid. But, even more, he said, the fact that faith motivates people's involvement means that the organizations are solid and permanent.