The premier of Victoria has ordered a review of the parole laws in the Australian state in the aftermath of the killing of Jill Meagher.

Denis Napthine was speaking at a press conference after the sentencing hearing for 41-year-old Adrian Bayley, who has admitted raping and murdering the Irishwoman in Melbourne last year.

It emerged in court that Bayley had a history of violent attacks on women spanning two decades, and that the Victorian Parole Board failed to cancel his parole after a violent assault.

Mr Napthine conceded that the parole system had failed Ms Meagher, and ordered a former High Court justice to review the structure of the board.

At the sentencing hearing at the Supreme Court of Victoria Bayley was described as a "violent sexual offender" with a "degree of sexual depravity rarely seen" in the Australian system.

He had previously pleaded guilty to raping and murdering Ms Meagher last September as she walked home from a nearby bar.

The court heard that he had a history of violent sex attacks and had previously raped 21 times, the first time when he was 18.

Bayley's barrister told the court that Bayley said he was sorry for what he had done and was seeking a life sentence, but without a mandatory minimum duration.

Ms Meagher's husband, family and friends described to the court the devastating impact her murder and rape have had on them.

Breaking down as he delivered his victim impact statement, her father George McKeown spoke of how her killing had destroyed their family and stolen her future.

The court heard how her husband Tom is haunted by what happened, wishing he could have told her he loved her in her final moments.

He said he suffers anxiety and panic attacks now, and is only half a person without his wife who he described as having a beautiful mind and a brilliant soul.

The court has been adjourned and Mr Justice Geoffrey Nettle will hand down sentence next Wednesday.