Held under blue skies and sunshine at Sydney's St Mary's Cathedral on Thursday, Pell was remembered as the son of a publican who rose to become the most senior Australian in the Catholic Church.

Mourners packed the cathedral for the controversial figure's requiem mass, while others gathered outside to watch the service on screens.

NSW Police riot squad units formed a human barrier between protestors and those attending the funeral, of the former Catholic archbishop of Melbourne and Sydney who died in Rome last month aged 81.

Before the mass begun a scuffle occurred outside the cathedral's main entrance when a woman accused a group of men of ripping down posters and ribbons in honour of child sexual abuse victims.

Across the road, protestors led by Community Action for Rainbow Rights, chanted "George Pell go to Hell".

Inside the cathedral, Sydney's Catholic Archbishop Anthony Fisher led the mass and paid tribute to his friend, 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.

Cardinal Pell was a bold and brave advocate for the Catholic Church who brought World Youth Day to Australia and "remained very much an Australian until the end", he told the congregation.

He said the "giant of a man" had a big heart, and that when he was ordained at the Vatican he adopted the motto "Be not afraid".

READ MORE

The Vatican ambassador to Australia, Charles Balvo, read a message from the Pope during the service thanking his "faithful servant" for his work reforming the Church's finances.

He said that as Vatican treasurer Cardinal Pell diligently implemented "economic reform for which he laid the foundations with determination and wisdom".

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 in the congregation.

"He found an echo of Christ even in the worst sinner," Mr Abbott said of Pell during his words of remembrance at the mass.

The former prime minister added he was not surprised Pell became a target.

"He was made a scapegoat for the church itself," Mr Abbott said to thunderous applause from those gathered outside watching the livestreamed service. "He should never have been charged in the absence of corroborating evidence."

Mr Abbott also joked the protestors may have become believers after all due to their chants "George Pell go to hell".

"At least they now believe in the afterlife, perhaps this is Saint Pell's first miracle," he said.

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

Rally organiser Kim Stern said the protesters would abide by police directions as they chanted and heard speeches by LGBTI and abortion rights activists.

"We want a strong, loud, vibrant and visible rally to oppose everything Pell stood for," he said.

Sydney man John Hill, 83, was among those to tie a colourful ribbon to the cathedral's gates in memory of those who suffered sexual abuse by clergy were removed overnight.

"I'm here to really feel empathy with the victims of paedophilia and the gay movement," he said. "It's just one way of saying something's not right."

Mr Hill said he knows a victim of paedophilia by the clergy, but declined to provide further details.

Pell was credited with cleaning up the Vatican's finances, but spent the later part of his life fighting a conviction over historic child sexual offences. He was jailed for 406 days before the High Court set aside his conviction and acquitted him of all charges.

Pell's brother, David Pell, spoke during the mass of how his brother's incarceration had an impact on their family.

He told those gathered how his brother was strip searched upon entering jail, and how he was "unjustly convicted for his predecessor's failings".

He also reminisced how his brother had loved "meat pie day" each Saturday in jail during his more than 12 months behind bars.

Following his death, conservative former Prime Minister Tony Abbott said Pell's jail time was a "modern form of crucifixion" and he should be made a saint.

Following the mass, Pell's body was laid to rest in the cathedral crypt in a private ceremony.

- with Australian Associated Press