A former high-ranking Catholic known for hosting boozy parties will spend at least four and a half years behind bars for sexually abusing two young Aboriginal men.

Ex-bishop of Broome Christopher Alan Saunders, 76, was found guilty of 13 sex offences following a jury trial in the West Australian District Court.

The offending between 2008 and 2019 included one count of sexual penetration without consent and a dozen unlawful and indecent assault charges.

Saunders was sentenced on Wednesday to six years and six months' imprisonment.

He will be eligible for parole after serving four years and six months.

Unless acquitted on appeal, the long-serving bishop would be the highest-ranking Catholic in Australia convicted of sexual abuse over his time as a member of the clergy.

The late Cardinal George Pell was found guilty in 2018 but later acquitted by the High Court of raping one choirboy and molesting another in 1996.

Saunders was acquitted by the jury of six other charges, including two counts of indecently dealing with a child over 16 under his authority and four counts of unlawful and indecent assault.

He was acquitted of a further seven similar charges during the trial due to the lack of evidence.

The sentence was backdated to August 12 when Saunders was convicted and taken into custody.

Saunders, who was known as "Brother B" by his victims, put on alcohol-fuelled parties at Catholic Church-owned properties to get access to Aboriginal boys and men so he could sexually assault them.

The offending included unwanted touching of genitals and kissing, often after Saunders had supplied the men with large amounts of alcohol.

Saunders was ordained as the second Broome bishop in 1996 and presided over 13 schools and nine parishes before stepping aside in 2020 when the sex abuse claims became public.

Pope Francis accepted his resignation a year later.

A church probe into the retired clergyman's activities was suspended when the West Australian police started investigating him.

It is set to restart now the trial has finished.

"Its findings will inform decisions in Rome about Christopher Saunders' position in the church," Archbishop Timothy Costelloe said in August.

Archbishop Costelloe said the jury's guilty verdict concerned crimes "that violate the dignity and betray the trust of victims and survivors".

"The victims, survivors and other witnesses who came forward showed great courage and resilience throughout a long and difficult process," he said.

Australian Associated Press