A drug-addicted anaesthetist who infected his patients with hepatitis C was inadvertently syringe-sharing, a court has heard.

Defence barrister John Dickinson SC told the Victorian Supreme Court on Tuesday James Latham Peters did not realise the same syringes he used to inject himself with fentanyl would then be used on his patients.

Peters, 63, has pleaded guilty to 55 counts of negligently causing serious injury, after infecting women with hepatitis C at a Croydon abortion clinic.

Mr Dickinson said Peters was exposed to drug use after marrying a heroin addict and had become "hopelessly addicted" to opiates by the mid-1990s.

He said it was "mind boggling" that Peters was registered to work as an anaesthetist where he could readily access fentanyl, his drug of choice.

"It's a little bit like putting a sugar-addicted child in a candy store and saying `behave yourself'," Mr Dickinson said.

But he said Peters had not realised he was placing his patients at risk.

"At no stage did he believe he was using the same syringe he used to inject himself, but he accepts he did," Mr Dickinson said.

Justice Terry Forrest said he struggled to believe that proposition.

"It's hard for me to accept that a man as accomplished and intelligent as your client obviously is, has no appreciation whatsoever he was placing these women in danger of injury by his conduct," Justice Forrest told Mr Dickinson.

The prosecution has called for a jail term of between 14 and 16 years.

Justice Forrest will sentence Peters at some stage after February 25.