Pedophile priest Gerald Ridsdale can't remember a boy he abused in NSW, whose family visited him in jail not knowing about the abuse, an inquiry heard.

The family of a boy abused by pedophile priest Gerald Ridsdale in NSW visited him in jail in Victoria, not knowing their son was molested, the royal commission has heard.

Ridsdale said he could not remember offending against a child when he went to live at White Cliffs in NSW, after stepping down from parish work in 1988.

"I can't think of anyone that I did," he told the child sex abuse royal commission's Ballarat inquiry on Thursday.

Senior counsel assisting the commission Gail Furness SC said there was a family Ridsdale met and became friendly with.

"That family don't know that you abused their son and they have visited you in jail over the 20-odd years that you've been in jail," Ms Furness told Ridsdale.

"Does that help you recall the abuse?"

Ridsdale said: "No, it doesn't."