He was also a sexual predator, molesting at least 14 adolescent boys under the guise of medical treatment at his practices at St Ives and Whalan as well as Royal North Shore Hospital in the 1970s and 80s.

Seven of his victims, now men in middle age, gave harrowing accounts of their abuse to the Royal Commission into Institutional Responses to Child Sexual Abuse, which finished its hearing into healthcare providers and regulators on Friday.

All spoke of their deep sense of betrayal, with one witness observing: "Who can you trust if not your family doctor?"

Just as doctors hold a position of trust, sick children hold a position of vulnerability, a point made by a witness who was molested by two volunteers in 1981 when she was a 12-year-old patient (known as AWI) at the Royal Children's Hospital, Melbourne.

"My abuser was extremely predatory," she said. "He targeted unwell, vulnerable and isolated children . . . Volunteering on the respiratory ward meant that the abusers knew the real possibility that their victims and their stories may pass away."

While AWI knew what happened to her was wrong at the time, Rolleston's victims told the commission they initially believed they were receiving legitimate medical treatment when the doctor asked them to undress and masturbate to provide semen samples to be tested for infection.

"The doctor held a position of authority and I was not allowed to question adults, however I felt the exam was strange," recalled one witness who was abused when he sought treatment for a sore throat in Rolleston's Whalan surgery. "It didn't seem to be going near the areas I had complained about."

Not only did Rolleston's status help him exploit young boys, it also made it harder for them to be believed, according to evidence before the commission.

Victim AWG told the commission his mother was dissuaded from complaining about Rolleston by a doctor friend who said: "It would be difficult to raise allegations and question the family doctor because he was a respected member of the community and that it would be unlikely that her word would be believed over Dr Rolleston's. (He) said words to the effect, 'You can't win on this'."

As the commission heard, the doctor was close to the mark. One victim, AWA, said he was rebuked when he tried to complain about Rolleston to the then NSW Medical Board when he was about 17 in 1977.

"The male on the telephone proceeded to threaten me and said, 'Please listen carefully. If you try to make a complaint against one of our members, we will come down so hard on you, we will sue you so that your head will be so far up your arse you won't see daylight for years'."

When AWI worked up the courage to disclose her abuse to the Royal Children's Hospital, Melbourne in 1984 she was accused of making a prank call. Thirteen years would pass before she lodged a formal complaint with the hospital, and the commission heard evidence her abuser continued to volunteer throughout that period.

A number of Rolleston's victims described their frustration with the Health Care Complaints Commission, the agency charged with handling allegations about practitioners.

Sydney businessman AWC alerted the HCCC to Rolleston in 1998. Three years later his complaint was suddenly terminated because investigators did not think there was sufficient public interest in the case. This was despite the fact Rolleston was still practicing in Broken Hill.

"I felt the HCCC did not want to upset the status quo and were more interested in protecting Dr Rolleston than they were in pursuing my complaint," he said.

Between 2002 and 2004, AWB complained about Rolleston to the HCCC, the Australian Medical Association, the Medical Board of NSW and the Department of Community Services.

"I was met with similar types of responses that didn't get me anywhere and was generally given the brush off," he said.

President of the Medical Council of NSW Peter Procopis​ gave evidence that a 1992 complaint about Rolleston from AWG was filed "somewhere" with no further action taken.

HCCC commissioner Kieran Pehm​ agreed the watch dog failed Rolleston's victims. He spoke of an organisation previously beset by lengthy delays, with hundreds of neglected complaints piling up and a poor information system that obstructed the cross checking of names.

"This is bad and it is indefensible," he said. "I'm sure the Commission is much better now than it was then," he said.

A number of victims eventually approached the police, who were praised in the commission for their swift response.

The commission heard Rolleston was arrested and charged with multiple sex offences against young boys in 2009 but continued to practise as a doctor with conditions placed on his registration. He was jailed in 2011 but his registration was not cancelled until 2013.

Now out on parole, Rolleston's sentence is due to expire next month. He will be able to reapply to practise as a doctor in 2017, which troubles his victims.

AWA recalled receiving a letter informing him that Rolleston would still be able to practise: "I was disgusted. I could not and still cannot fathom how the man who sexually abused me as a child, as well as many other young boys, could be allowed to be back in that position."

Adults Surviving Child Abuse: 1300 657 380

Child Wise 1800 99 10 99

Bravehearts: 1800 272 831