Pope Francis on Sunday elevated to sainthood the first female saint from his native Argentina, an event that brought to the Vatican his former vocal critic, Argentine President Javier Milei.

Milei, a maverick right-wing libertarian, had - before he ran for president - called Francis an "imbecile," but has softened his tone since taking office in December.

The pope, for his part, has said he did not pay too much attention to the insults, telling Mexican broadcaster N+ that what matters is what politicians do in office, rather than on the campaign trail.

Francis led a canonisation Mass in St. Peter's Basilica for Maria Antonia de Paz y Figueroa, better known as "Mama Antula", an 18th century consecrated lay woman who renounced her family's riches to focus on charity and Jesuit spiritual exercises.

The ceremony came as Argentina faces its worst economic crisis in decades, with inflation at more than 200%, and the newly installed Milei in difficulty following parliamentary rejection of a major reform package.

Milei had a front row seat for the service, and at the end of it, exchanged a few words with the pope, as they shook hands and hugged. The president is due to have a private audience with Francis on Monday.

Francis, a former archbishop of Buenos Aires who has angered some of his compatriots by never visiting his homeland since becoming pope in 2013, has said he may finally make the trip in the second half of this year.

Mama Antula was the daughter of a wealthy landholder and slave owner.

She promoted spiritual exercises, including prayers and meditation, walking thousands of kilometres barefoot and involving the rich and poor in these endeavours, despite the Jesuits being banished at the time from Latin America.

Francis, himself a Jesuit, described her on Friday as a "gift to the Argentine people and also to the entire Church."

Quoting from his past writings, the pope condemned the "radical individualism" that permeates society as a "virus", in words that may jar with Milei's radical free-market instincts.

In his homily on Sunday, he returned to the issue of caring for the poor and outcasts, saying "fear, prejudice and false religiosity" led people to the "great injustice" of ignoring the plight of the weak.

On Monday, wrapping up a week-long overseas tour that took him to Israel before Italy and the Vatican, Milei is also due to meet Italy's President Sergio Mattarella and Prime Minister Giorgia Meloni.