The Catholic Church and individual Christians must follow Christ by imitating his willingness to give up everything for the sake of others as St Francis of Assisi did, Pope Francis has said.

"Unfortunately, 2,000 years after the proclamation of the Gospel and eight centuries after the witness of Francis, we face a phenomenon of global inequity and an economy that kills," the Pope said to the archbishop of Assisi, Italy in a letter on Sunday.

The Pope's letter offered his blessings and support for the decision of the Diocese of Assisi to establish a shrine in memory of the "divestiture" of St Francis.