* Archdiocese says abuse commission confirmed complaints
* Amsterdam newspaper uncovered story
* Few bishops have been named as abusers themselves
By Tom Heneghan, Religion Editor
PARIS (Reuters) - The Dutch Catholic Church, in the second such embarrassing admission this month, announced on Friday that a bishop who died in 2000 had been found guilty of sexually abusing boys decades ago.
Utrecht archdiocese, where Johannes Nienhaus was auxiliary bishop from 1982 to 1999, said a commission investigating the scandals that have shaken the Catholic Church in many countries in the past decade had confirmed four complaints against him.
Earlier this month, Roermond diocese said its late bishop Johannes Gijsen had sexually abused two boys, also decades ago.
The Utrecht announcement came two days before the late Pope John Paul II, whom critics accuse of failing to investigate the clerical sex abuse scandal as evidence of it piled up in the later years of his pontificate, is to be declared a saint.
The Amsterdam daily De Volkskrant, which uncovered the story, said the abuse took place from the mid-1950s to the early 1970s when Nienhaus was chaplain and later rector of a junior seminary in Apeldoorn.
In his statement, Utrecht archdiocese said Cardinal Johannes Eijk, its current archbishop, took note of the four cases reported by the abuse commission and stressed they took place before Nienhaus was a bishop.
"Cardinal Eijk is sad that this abuse occurred and hopes the determination of the complaints' plausibility can help the healing process of the victims," the statement said.
The statement made clear the cases were being reported in response to queries from De Volkskrant, which said they had been confirmed by the abuse commission two years ago but not made public by the archdiocese at the time.
The newspaper said Nienhaus had indecently touched boys.
It quoted Guido Klabbers, head of the abuse victims' group Klokk, as saying: "The church says it wants to exercise full openness, but when it gets serious, it hushes up abuse cases, especially if they concern those higher up."
The abuse commission estimated in 2011 that up to 20,000 minors had been sexually abused in Catholic orphanages, boarding schools and seminaries since 1945, with offences ranging from very mild to serious, including rape.
Around the world, few bishops have been accused of active abuse in the scandal, which has been rocking the Catholic Church for over two decades. Most of the prelates who have stepped down did so for covering up the misdeeds of their priests.
Two cardinals - Hans Hermann Groer of Vienna and Edinburgh's Keith O'Brien - quit in disgrace amid accusations of sexual misconduct with seminarians. A Belgian bishop, Roger Vangheluwe of Bruges, stepped down after admitting molesting his nephew.
The Vatican has been investigating sexual abuse allegations against Archbishop Josef Wesolowski, its former nuncio (ambassador) to the Dominican Republic, since last September. His whereabouts and the status of his case are not known.
Pope Francis, who has been criticized by victims' support groups for not taking a sufficiently strong stand against sexual abuse, named a high-level group in March that included an Irish abuse victim to help fight sexual abuse in the Church.
Earlier this month, he made his first public plea for forgiveness for "all the evil" committed by priests who molested children, and said the church had to do more to discipline wayward clerics.
Reporting by Tom Heneghan; editing by Andrew Roche