The Catholic Archbishop of the US island territory of Guam, Anthony Apuron, has been definitively convicted of sexual abuse of minors and removed from office, the Vatican has said.

Apuron, who was accused of abusing three young men decades ago, was first convicted by a Vatican tribunal a year ago and had appealed.

He has denied wrongdoing.

But according to today's statement, the tribunal at the Vatican's Congregation for the Doctrine of the Faith upheld the first verdict on the man who had led the church in Guam for three decades.

Apuron, 73, and a native of Guam, was removed from office and prohibited from living on the island, even temporarily, the Vatican said.

The allegations first emerged in 2016 when one of the victims, a former altar boy, came forward when he was in his 50s and other victims followed.

The Vatican said the decision announced today was definitive and could no longer be challenged on appeal.

 Apuron had served as the island's archbishop since 1986.

The church's credibility has been crushed in much of the world by abuse scandals in countries including Ireland, Chile, Australia, France, the United States and Poland, paying billions of dollars in damages to victims and forcing parishes to close.

The scandals have reached the upper echelons of the Vatican itself with the conviction of Cardinal George Pell, jailed this month for six years for abusing boys in his native Australia.

He had served as the Vatican treasurer and a member of the pope's innermost council of cardinals until his conviction last year.

Other senior church officials have been accused of knowingly covering up abuse, including the archbishop of Lyon who was convicted this year in France for failing to report abuse.

Archbishop Michael Byrnes, a former assistant bishop of Detroit, succeeds Apuron as archbishop of Guam's single archdiocese, Agana.

The archdiocese, which has been hit by a number of lawsuits by victims of abuse, has filed for reorganisation bankruptcy in the island's district court.

Guam's population of about 170,000 is predominantly Catholic.