Child sexual abuse survivor Peter Saunders says he will not be silenced by the church despite the threat of legal action by Cardinal George Pell, Australia’s most powerful Catholic.

During a TV interview on Sunday night, Saunders – who was appointed by Pope Francis to lead the Vatican’s commission for the protection of children – accused Pell of lacking compassion for those abused within the church.

During the interview, Saunders called on the pope to remove Pell from his position as head of the Vatican’s finances, saying his alleged involvement in covering up abuse and protecting paedophile priests made his position “untenable”.

The comments prompted a swift reaction from Pell, whose spokesperson issued a statement on Sunday night saying; “In the circumstances, the cardinal is left no alternative but to consult with his legal advisers.”

The pope’s spokesman Federico Lombardi said Saunders was expressing his “personal views” and not those of the commission. Pell’s response to allegations against him “must be considered reliable and worthy of attention and respect”.

But on Tuesday Saunders told Guardian Australia: “Our church has a history of spending millions on defending paedophiles.

“George Pell, obviously a wealthy man, will think nothing of using his wealth to silence me but I have said nothing that others haven’t said and it is only my opinion.

“It is not slanderous.”

Saunders established the National Association for People Abused in Childhood in Britain 16 years ago and was hand-picked by the pontiff to work with the Vatican. As a child Saunders was abused by two Jesuit priests and the head of a Catholic primary school.

The Archbishop of Melbourne, Denis Hart, defended Pell on Tuesday morning, telling ABC radio in Australia that Saunders’s descriptions of Pell “doesn’t fit the man”.

“I would describe George Pell as a man who courageously, when he became archbishop, introduced the first system for dealing with child sex abuse, trying to bring relief to victims, trying to bring care and also some financial compensation,” Hart said.

“And he was a world leader in this regard.

“He’s made some mistakes and he has admitted them and apologised for them. But very clearly he comes across as someone who is totally dedicated to putting right this awful, awful scourge.”

On Monday, the royal commission into institutional responses to child sexual abuse, which since 2013 has been investigating how Australian institutions handled allegations of abuse, said Pell had been invited to personally appear before the commission when it returns to Ballarat in Victoria later this year.

During the first round of hearings in Ballarat in May, the commission heard damning evidence from a victim who alleged Pell bribed him to keep quiet about being abused by a senior Catholic priest.

“In the ordinary course, witnesses are summonsed to appear at a hearing,” the commission spokeswoman said.

“However a person resident overseas cannot be summonsed. The chair has received a letter from Cardinal Pell indicating that he is prepared to come to Australia to give evidence. The royal commission will ask him to give evidence in the second of the Ballarat hearings.”

Pell has previously appeared twice before the commission, however, via video-link from Rome.