Thousands of mourners and religious leaders from around the world packed Sydney’s St Mary’s Cathedral on Thursday for the controversial figure’s requiem mass.

Others gathered to watch on screens outside, while crowds of protesters assembled across the road to demonstrate against the commemoration.

The 81-year-old former Catholic archbishop of Melbourne and Sydney died in Rome last month and was buried in the cathedral’s crypt, alongside seven other former archbishops.

Sydney Catholic Archbishop Anthony Fisher celebrated the final mass for his friend, describing him as the son of a Ballarat publican, who spent 56 years as a priest and rose to become the third most powerful man in the Catholic Church.

Pell was a bold and brave advocate for the Catholic Church who brought World Youth Day and Pope Benedict XVI to Australia in 2008 but “remained very much an Australian until the end”, Fisher told the congregation.

He said the “giant of a man” had a big heart and when he was ordained at St Peter’s Basilica at the Vatican he adopted and lived by the motto “Be not afraid”, eventually serving under three popes.

Fisher addressed the elephant in the cathedral early in the service, referring to the 404 days the cardinal spent in jail after being convicted of molesting two teenage choirboys in 1996. The convictions were later quashed.

“Even after he was unanimously exonerated by the High Court, some continued to demonise him,” Fisher said.

“But many appreciate the legacy of this most influential churchman in our nation’s history.”

In a eulogy for his brother, David Pell denounced the child sexual abuse allegations as a “relentless campaign to smear George’s life”.

“We implore you to rid yourselves of the woke algorithms of mistruths, half truths and outright lies that are being perpetrated,” he said.

Police riot squad units remained outside the cathedral to ensure safe distance between mourners and the protesters who marched past the building’s forecourt during the service chanting “George Pell go to hell”.

Vatican ambassador to Australia Charles Balvo read a message from Pope Francis, thanking his “faithful servant” for his work reforming the church’s finances.

As Vatican treasurer, Pell had diligently implemented “economic reform for which he laid the foundations with determination and wisdom”, he said.

Opposition Leader Peter Dutton, former prime ministers John Howard and Tony Abbott, media personality Alan Jones and divisive politicians Mark Latham and Matt Canavan were among those attending.

Abbott also spoke about his friend, calling the cardinal a “great hero” who was made a scapegoat and equating his time in prison to “a modern-day crucifixion”.

“George Pell was the greatest man I’ve ever known,” he said.

Prime Minister Anthony Albanese, NSW Premier Dominic Perrottet and Opposition Leader Chris Minns were notable absentees.

An 11th hour compromise was reached on Wednesday to allow a protest organised by LGBTQI group Community Action for Rainbow Rights.

“We’re not here to cause trouble, we’re here to bring attention to the abuse, that’s all,” protester Max Elbourne told AAP.

Thousands of colourful ribbons attached to the cathedral’s gates in memory of those who suffered sexual abuse by clergy were removed overnight.

Tensions flared briefly when some mourners tried to take down others tied to a small area of cathedral fence where the church had allowed them to be displayed.

Cardinal Pell’s conservative stance on gay marriage and abortion were the subject of criticism throughout his life. He also faced allegations of covering up child abuse.