Abuse victims have hit out at comments made by Pope Francis after he labelled the church's critics "friends of the devil".

Key points: Pope Francis said those who spend their lives accusing the church are related to the devil

Pope Francis said those who spend their lives accusing the church are related to the devil Victims said the comments resembled a "Trumpian tantrum"

Victims said the comments resembled a "Trumpian tantrum" The Pope has called for "concrete" steps to combat child sexual abuse in the church

During a speech to pilgrims from southern Italy on Wednesday, Pope Francis said "defects" from the church had to be denounced so they could be corrected, and those who criticise "without love" were linked to the devil.

"One cannot live a whole life of accusing, accusing, accusing, the church," Pope Francis said.

"Who is the accuser? Who in the Bible is called the Great Accuser? The devil.

"Those who spend their lives accusing, accusing, accusing are not the devil's children because the devil has none.

"[They are] friends, cousins and relatives of the devil, and this is wrong."

The comments were made on the eve of the Vatican's landmark summit into the protection of minors, with 190 bishops and heads of Catholic religious orders travelling to the Holy See to ensure church leaders are held accountable to victims.

Pope Francis said "defects" from the church needed to be denounced so they could be corrected. ( AP: Andrew Medichini )

British victims' advocate Pete Saunders said the Pope's comments proved he was "not really interested in bringing real change".

Mr Saunders was previously a member of the Pontifical Commission for the Protection of Minors but was put on leave when he openly chastised the Pope's response to revelations of clerical abuse in Chile.

"To attack us and to say that we are friends, relatives and cousins of the devil, I put it down to a kind of Trumpian tantrum," Mr Saunders said.

"I think whatever credibility the Pope had, I think has now been completely extinguished."

Mr Saunders said the Pope's comments could even endanger people in some parts of the world where his words are followed very closely.

"It may endanger the lives, actually endanger the lives of survivors who speak out," he said.

"And of course, it may even endanger the lives of priests and others around the world."

During the opening address of the summit at the Vatican, Pope Francis told church leaders to "hear the cries of the little ones", and urged bishops to consider "concrete" measures to deal with the abuse crisis.

"The holy people of God look to us and expect from us not simple and obvious condemnations, but concrete and effective measures," he said.

Sorry, this video has expired Reactions to Pope Francis' proposals to stem clergy sex abuse

The summit heard harrowing testimonials from victims of abuse, including a woman who said she was raped by her parish priest over the course of 13 years.

The survivor said she fell pregnant three times but the priest forced her to have multiple abortions.

Archbishop of Brisbane Mark Coleridge said the Pope had given strong indications of the types of changes he would like bishops to consider.

He said the abuse crisis could prompt a "renegotiation of the relationship between church and state".

But he said he would not budge on his view of upholding church secrecy rules for confession, meaning clergy do not have to report priests who disclose abuse in confession.