Cardinal George Pell [Photo: AFP/Getty Images]

Cardinal George Pell - the Vatican's former treasurer - has been jailed for six years for sexually abusing two boys.

He was jailed by an Australian court for assaulting the two choir boys in the 1990s at St Patrick's Cathedral in Melbourne.

Pell, 77, is the highest-ranking Catholic priest worldwide to be convicted for child sex offences.

He was convicted in December of orally raping one of the 13-year-old choir boys - and indecently dealing with him and the boy's friend, also 13.

[Photo: AFP/Getty Images]

The assaults happened just months after Pell became Archbishop of Melbourne.

A court order had blocked media reporting the news until last month.

Pell denies the allegations and will appeal against his convictions in June.

"In my view, your conduct was permeated by staggering arrogance," County Court of Victoria Chief Judge Peter Kidd said in the sentencing, which took more than an hour.

"Viewed overall, I consider your moral culpability across both episodes to be high."

Pell, pictured with Pope Benedict in 2013 [Photo: AFP]

The judge set a non-parole period of three years and eight months.

Pell will be registered as a sex offender for life, he added.

The ex-priest, who was found guilty in December, has maintained he is innocent and has filed an appeal on three grounds.