OSLO (AFP) - A German-born former Catholic bishop has admitted to sexually abusing a minor in Norway 20 years ago, the Norwegian Church revealed Wednesday, in the latest paedophilia scandal to rock the Catholic Church in recent months.

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"The Catholic Church in Norway is in shock after it was revealed that former bishop Mueller of Trondheim (on Norway's western coast) admitted being guilty of sexual abuse of a minor and said that was why he left his post last year," the Church said in a statement.

Georg Mueller, 58, who was born near Trier in Germany, suddenly left his diocese in Trondheim in June last year, officially because he had trouble cooperating with other staff there.

The affair reportedly dates back more than 20 years to when Mueller was a priest in Trondheim. The victim was a choir boy, who is now around 30 years old.

The Church had found out about the abuse allegations in January 2009, and after an internal investigation, the Vatican decided Mueller had to go, the local daily Adresseavisen, which broke the story, reported.

Mueller, a priest since 1978 and bishop of Trondheim between 1997 and 2009, "confessed as soon as he was confronted with this," the current Bishop of Trondheim and Oslo, Bernt Eidsvig, told the paper.

There was no indication that Mueller had abused other children, he said.

"He has insisted that that is not the case. And as far as I know, no one else has come forward with claims to police or other authorities," he said, acknowledging however that he could not be "100 percent sure" that there were no other victims.

Details of the abuse had not been released earlier "at the request of the victim," the Church said, adding that it had not reported the case to police since the victim today was an adult and it was too late, due to a statute of limitations, to prosecute the case under Norwegian law.

"If the victim in this case had wished, we would have" gone public, Eidsvig told Adresseavisen, adding that he was glad the Church had acted as quickly as it had in this case, and stressing there was no time limit to Church justice.

"That is why Mueller today no longer has a position in the Church," he said.

"This is a very sad case, but I pray for everyone involved and that the Church will get through this," he added.

Eidsvig meanwhile told the NRK public broadcaster that he was aware of three other abuse cases within the Norwegian Catholic Church.

"Two of the cases are very old. They happened at the beginning of the 1950s," he said, adding that the victims, a boy and girl, were now in their 70s and both the priests were dead.

The Church had found out about a third case about 10 years ago, but the statue of limitations had passed, and the Church had not been able to get hold of the foreign priest responsible for the abuse, who had left the country, he said.

The revelation of Mueller's abuse is only the latest to rock the Catholic Church, after large-scale paedophilia scandals have rocked the churches of Ireland, Austria, the United States and the pope's native Germany.

The pontiff, 82, has himself faced criticism over claims that, as Cardinal Joseph Ratzinger when he headed the Vatican's watchdog over morals and doctrinal issues, and earlier as the archbishop of Munich, he failed to take action against predator priests.