James Latham Peters, 63, has pleaded guilty to 55 counts of negligently causing serious injury to the women patients by infecting them with the potentially deadly blood disease while they underwent pregnancy terminations at the Croydon Day Surgery between June 2008 and November 2009.

His defence barrister John Dickinson, SC, told a pre-sentence plea hearing in Victoria's Supreme Court on Tuesday that after injecting himself in private with the opioid he was addicted to, fentanyl, Peters failed to realise the same syringe which contained "blowback", or his contaminated blood, was then used on the patients.

"At no stage of what he did did he intend to use the same syringe, but he did," Mr Dickinson said.

He said Peters became exposed to drugs after he married his second wife in 1991. By the mid-90s he was "hopelessly addicted".

Despite being suspended by the now defunct medical board of Victoria – at his own request – in 1996, Mr Dickinson described it as "mind-boggling" that an addict would then be allowed to go back to work where he would be put in a situation where he would have easy access to the drug he was addicted to.

"It was catastrophe waiting to happen, which did eventuate. It is a little bit like putting a sugar-addicted child in a candy store and saying 'behave yourself'," he said.

Peters had a complete relapse after his wife died at the age of 38 in 2003, the court said.

He was diagnosed in 2005 with cancer, which required drastic treatment, and currently suffered from not only his opiate dependency, but also emphysema, asthma and bronchitis. His client also suspected he was showing signs of early onset Alzheimer's, the court heard.

Mr Dickinson said after the hepatitis C outbreak from the clinic was exposed in 2010, Peters' downfall had been "spectacular".

"He has spent the last two years or more in complete solitude," he said. "He has withdrawn from the world."

Peters had lost his career, his name was now infamous and "he's fallen a long way", he added.

Peters' two daughters and his sister were his only supporters.

Mr Dickinson urged Justice Terry Forrest to consider his client's guilty plea as a sign of remorse, which he said came at an early stage, and thus prevented his victims from having to give evidence at a trial.

"Yesterday's [victim impact statement] evidence was very emotional, very powerful but one has to ... not be overwhelmed by the evidence. He has pleaded guilty to negligently causing serious injury and it's important to note, there's no allegation of intentionally causing serious injury and no allegation of recklessly causing serious injury."

He stressed that his client was an addict, which research suggested was a disease that caused otherwise reasonable and intelligent people to resort to incredulous behaviour in order to obtain their drug of choice.

But Justice Forrest, who now has the task of sentencing Peters, said: "It's hard for me to accept that a man as accomplished and intelligent as your client ... had no appreciation whatsoever that he was placing these women in danger by his conduct.

"He knew he had hepatitis C. He knew that he was using a syringe to inject fentanyl into his system. He must have appreciated there was a danger of blowback, his own blood into the syringe," the judge said.

He described Peters' actions as a "gross and unjustifiable departure from the standard of care expected from an anaesthetist", and said a strong message had to be sent to other recovering doctors working in the medical field that such behaviour would not be tolerated.

The charge carries a maximum of 10 years' jail on each count.

Chief Crown prosecutor Gavin Silbert, SC, called for him to be sentenced to between 14 and 16 years.

Justice Forrest will sentence Peters after February 25.