The Vatican on Tuesday will release its long-awaited report into what it knew about ex-cardinal Theodore McCarrick's sexual misconduct during his rise through the church hierarchy, setting up a remarkable moment in the Vatican's long reckoning with clergy sexual abuse and cover-up.

The Vatican said on Friday the report would span McCarrick's entire life, from his birth in 1930 to the 2017 allegations that brought about his downfall.

The Vatican said the report would cover "the Holy See's institutional knowledge and decision-making process" as McCarrick rose through the church's ranks.

Francis defrocked McCarrick in February 2019 after a Vatican investigation determined he sexually abused minors as well as adults.

The 90-year-old is believed to be living in a retirement community as a layman.

The scandal erupted amid the revelations of a Pennsylvania grand jury's report on abuse by clergy and sparked a credibility crisis for the US and Vatican hierarchies, since it was an open secret that McCarrick slept with adult seminarians.

Yet McCarrick still rose to the heights of church power, even acting as the spokesman for US bishops when they enacted a "zero tolerance" policy against sexually abusive priests in 2002.

Pope Francis authorised a "through study" of the Vatican archives for information about McCarrick in October, 2018, two months after the former Vatican ambassador to the United States, Archbishop Carlo Maria Vigano, accused Francis of being the last in a long line of Vatican and US churchmen to cover up McCarrick's misconduct.

Archbishop Vigano's accusation provided detailed evidence that the Vatican was well aware of McCarrick's penchant for sleeping with his seminarians as early as 2000.

Even though the archbishop demanded Francis's resignation over the scandal, it was actually Francis who authorised a canonical investigation into McCarrick's behaviour after a man came forward to New York church authorities in 2017 and alleged McCarrick groped him when he was a minor.