A psychologist at Sydney's Royal North Shore Hospital sexually abused a patient in the late 1960s, telling the boy it would cure his asthma, an inquiry has been told.

The Royal Commission into Institutional Responses to Child Sexual Abuse also heard damning revelations of poor record keeping and a lax attitude towards child protection at the time.

The revelations on Monday led to public apologies from the hospital's chief executive officer and the New South Wales Health Department.

Terence Kirkpatrick was referred to a psychologist at the hospital in 1967 to be treated for asthma, which was then considered to be emotionally-induced.

The psychologist was Stuart Frank Simpson, who first saw Mr Kirkpatrick when he was 11 years old.

"My mother waited outside the consulting room in the waiting area," Mr Kirkpatrick told the hearing.

"Simpson would have sit back in a chair. He would say 'relax, close your eyes'.

"I understand now that he was trying to hypnotise me, but I didn't really know what was going on. Simpson would then make me dress up, photograph me, and make me perform oral sex."

Mr Kirkpatrick, now 59, remembered how he felt each time he had to see the man he was told to trust.

"I received no treatment for my asthma during that time," he said.

"I recall the absolute fear that I held at home the night before I knew I had an appointment with him, and I felt increasingly fearful on the journey there.

"In the waiting room before I saw Simpson, I remember feeling very deep terror."

Now a psychologist himself, Mr Kirkpatrick realised he was being groomed.

"I experienced a perfect storm of emotions that I was too young to understand or cope with," he said.

"When the emotion subsided, I was left with this overwhelming feeling of bewilderment and helplessness.

"It was like I was in a dark, damp place desperately searching for someone to help me."

When Mr Simpson asked to meet Mr Kirkpatrick in a nearby national park, he reported the abuse to his parents.

They complained to the hospital, but the hearing was told nothing was done.

Records may have been destroyed, never kept

Northern Sydney Local Health District chief Associate Professor Vicki Taylor was asked by Counsel Assisting Hayley Bennett if there was any record of the complaint and if they existed whether they could have been destroyed.

"They could have been destroyed. The other possibility is that there wasn't a written record kept of that contact," Associate Professor Taylor said.

She told the hearing Mr Simpson's employment records may have also been destroyed as part of the hospital's standard procedures.

Today, records are kept for 75 years.

Associate Professor Taylor said mandatory reporting requirements and working with children checks were now standard.

Recruits were also told how to respond to reports of abuse in a two-hour training session.

'I apologise for what has been experienced'

Associate Professor Taylor acknowledged that if these steps had been in place, the chances of abuse would have been minimal.

"I apologise for what has been experienced by the survivors," she said.

"The delays, the loss of records. I want to assure you all that Royal North Shore Hospital is a very different place these days."

The apology was echoed by the secretary for NSW Health Dr Mary Foley.

"It shouldn't have happened. Something like this should never happen, and I'm sorry that it has happened," she said.

"I can assure the commission that my focus, and our focus, is on all the things we can do and implement effectively that can stop this happening again."

Mr Simpson was never held to account for the alleged abuse of Mr Kirkpatrick.

Mr Kirkpatrick also said he believed Mr Simpson was not a qualified psychologist.

It is believed Mr Simpson is now deceased.

Mr Kirkpatrick said he hoped that by him coming forward people would learn to be more aware of the behaviour around them.

"Taking photographs of a child has nothing to do with therapy or treatment, and is again another alert signal for a supervisor working with a health practitioner," he said.

"When any member of staff in health care practices has concerns about a colleague inappropriately treating a child, it needs to be immediately addressed and dealt with."

The hearing continues tomorrow when focus will shift to the Royal Children's Hospital in Melbourne.