Pope Francis on Tuesday called on priests to pardon women who have abortions, and the doctors who perform them, during the upcoming Jubilee year -- overruling hardline traditionalists within the Catholic Church.

"I have decided, notwithstanding anything to the contrary, to concede to all priests for the Jubilee Year the discretion to absolve of the sin of abortion those who have procured it and who, with contrite heart, seek forgiveness for it," he said.

In a message outlining special measures for the Jubilee, Francis said he knew that while "the tragedy of abortion is experienced by some with a superficial awareness... many others... believe that they have no other option".

The Argentine pontiff said he was "well aware of the pressure" that some women were under to abort, adding that he had "met so many women who bear in their heart the scar of this agonising and painful decision".

The 78-year-old, who has repeatedly urged the Church to show greater compassion, said priests should use "words of genuine welcome", as well as making sure those involved were aware of "the gravity of the sin committed".

Francis announced earlier this year a Jubilee year -- traditionally a time for remission and forgiveness -- which will run from December 8 to November 20 and be celebrated not only in the Vatican but in dioceses across the world.