Archbishop Josef Wesolowski, 65, was removed in August from his post as Holy See ambassador to the Dominican Republic after allegations surfaced in the media of child sexual abuse, dpa reports.

After an investigation into the matter, the Congregation for the Doctrine of the Faith, the Vatican's disciplinary watchdog, convicted him and deemed him no longer fit to serve as a priest, a statement said.

Wesolowski has two months to file an appeal against that decision.

Until then, "all the actions that are commensurate to the seriousness of the case" will be taken against the archbishop, the Vatican said, in remarks that were seen as hinting at the possibility of an arrest.

Once the sanctioning procedure, conducted under canon law, is complete, Wesolowski will face separate criminal proceedings before Vatican City State courts, the statement added.

The Catholic Church's reputation has been seriously tarnished by worldwide revelations about paedophile priests, and by allegations that for decades its hierarchy failed to punish them or even covered up their crimes.

Pope Francis issued an unprecedented apology in April for the abuses.

"The Church is aware of this damage, it is personal, moral damage carried out by men of the Church, and we will not take one step backward with regards to how we will deal with this problem, and the sanctions that must be imposed," he said.