Pope Francis declared two martyrs, four priests and a mystic nun saints of the Catholic church on Sunday, saying they all had a "generous and steadfast heart".

Tapestry portraits of the seven saints, hung from the facade of St Peter's Basilica, rippled in the breeze above the main square at the Vatican where Francis led the ceremony.

Assembled pilgrims applauded as he read out the names of the new saints, defined by the church as having been so holy in life they are now in Heaven and can intercede with God to perform miracles - two of which are needed to declare sainthood.

President Mauricio Macri of the pope's native Argentina attended the ceremony, during which Francis elevated Argentine pastoral priest Jose Gabriel del Rosario Brochero.

Brochero, who rode a mule around a vast region of Cordoba province, preaching and building schools, churches and streets, "smelt of sheep", the Vatican said, referring to Francis's call for priests to behave like shepherds.

He contracted leprosy while visiting the sick, and the disease eventually killed him in 1914.

Two martyrs were also added to the Church's more than 10,000-strong roster of saints. Jose Sanchez del Rio was tortured and shot dead in 1928, at the age of 14, while opposing the anti-Catholic regime in his native Mexico.

The second, Salomone Leclerq, belonged to a religious order in France, where he was killed during the revolution in 1792.

French mystic nun Elizabeth Catez, known as Sister Elizabeth of the Trinity, died in 1906 at the age of 26 from a rare adrenal gland disorder for which there was then no cure.

Spanish bishop Manuel Gonzalez Garcia, who became known as the "Bishop of the Tabernacle" after a mystical experience in a church near Seville, was also elevated, along with Italians Father Lodovico Pavoni and Alfonso Maria Fusco, who founded religious congregations and worked with the poor in the 19th century.