Cardinal George Pell, formerly in charge of the Vatican's finances and a member of Francis' inner circle of advisers, has been found guilty of raping a choirboy and molesting another in the 1990s.

The Vatican called it "painful news" but, through spokesman Alessandro Gisotti, said it would not take any immediate disciplinary action.

"We await the outcome of the appeals process, recalling that Cardinal Pell maintains his innocence and has the right to defend himself until the last stage of appeal," Gisotti said.

Such caution is unlikely to be received well by victims and the wider public, especially after Francis and his predecessor Benedict XVI repeatedly vowed "zero tolerance" against clergy sex abuse.

"Any cleric who has been found guilty of even a single act of child sexual abuse, no matter when the act occurred, [should be] immediately removed from ministry and permanently removed from the priesthood," advocacy group Ending Clergy Abuse wrote in a Monday appeal.

Yet the Vatican's response is not surprising after last week's summit, in which apologies and promises of justice for victims were accompanied by mixed messages on the punishment of abusers.

In his closing speech to the summit on Sunday, Francis quoted a biblical passage calling for anyone who harms children "to have a great millstone fastened around his neck and to be drowned in the depth of the sea".

At the same time, he called for "the right balance" in the church's response to scandals, avoiding "justicialism", or summary justice, "provoked by guilt for past errors and media pressure".

Furthermore, a papal 21-point reform road map that the Vatican circulated at its February 21-24 conference included calls for proportional punishment towards sex abuse offenders.

In Pell's case, disciplinary measures could go as far as stripping him of his cardinal title and expelling him from the clergy, if the precedent of Theodore McCarrick holds.

McCarrick, a former archbishop and cardinal from the United States, was earlier this month found guilty by a church tribunal of soliciting sex from adults and minors, including during confession.

The difference with Pell is that he faces jail if his conviction holds on appeal while McCarrick has been spared from civilian justice due to the statute of limitations on his crimes.

In theory, the Pope could strip Pell of his cardinal rank at any moment while defrocking could only come at the end of a canonical disciplinary process.

Massimo Faggioli, a professor of Theology and Religious Studies at Villanova University, in the US, says there may be an additional motive for the Vatican to tread carefully in the case.

Last month, former Adelaide Archbishop Philip Wilson had a conviction for child abuse cover-up crimes, which had cost him his job, overturned by an Australian appeals court.

"This is a cautionary tale for the Vatican," Faggioli told dpa.

He noted that Pell's trial "has been far more controversial than any other involving higher Catholic clergy" because it was largely conducted "in secret".

This "makes it necessary to be overcautious," Faggioli argued. "The Vatican has already given up some caution by displaying absolute respect for the Australian justice system," he added.

Meanwhile, Pell's current status within the Vatican's administration remains unclear despite Vatican pledges to react to sex abuse cases with "transparency."

Pell's five-year mandate as Prefect of the Secretariat of the Economy expired on February 24 but Gisotti refused to say whether that meant Pell no longer held that position.

According to Faggioli, the once-powerful cardinal's career is over, whatever happens on appeal. 

"Pell is 77 and I do not think he will have another role in the Vatican again," he said.

Australian Associated Press