Melbourne’s Bourke Street killer James Gargasoulas has been sentenced to life in prison for killing six people and injuring 27 others when he drove his car through Melbourne's CBD in 2017.

Justice Mark Weinberg described the actions of James Gargasoulas as “one of the worst examples of mass murder in Australia’s history”, as he set a non-parole period of 46 years.

Gargasoulas - flanked by 10 officers - was led down the corridors of the Supreme Court into a courtroom filled with family and friends of the victims of the attack.

James Gargasoulas was sentenced today in Melbourne's Supreme Court. (9news)

Sitting in the dock pan-faced and surrounded by four prison guards, Gargasoulas learned from the bench that he would not become eligible for parole until age 76.

Weinberg said the convicted killer was “fortuitous” that more people weren’t killed or injured and did “not accept” that Gargasoulas was “genuinely remorseful”.

“The extraordinary nature of your offending means there are few if any legal precedents to rely on when sentencing,” Weinberg said.

The 29-year-old’s victims included three-month-old baby Zachary Bryant, who was thrown 60 metres from his pram, and 10-year-old girl Tahlia Hakin.

James Gargasoulas ploughed into pedestrians on Melbourne's packed Bourke Street, killing six and injuring many others. (AAP)

"The sentence is not harsh enough", families of five victims said in a joint statement.

Gargasoulas had an extensive criminal history dating back to 2008 which included assault, driving offences and weapons charges.

“You have shown yourself to be a persistent law breaker,” Weinberg said.

At the time of the attack, Gargasoulas was in a drug induced psychosis, and now suffers from paranoid schizophrenia.

In a letter read previously to the court, Gargasoulas insisted he was not evil and blamed "government oppression" for the murders.

Gargasoulas described what he believed were the government and monarchy's misdeeds in overruling "God's laws of liberty" and that the country's legal, social and financial systems were designed to "enslave humanity".

Justice Weinberg, however, said that "one could not but be profoundly moved by the terrible devastation that you, by your actions, brought about that day."

"I'm convinced, and so was the jury, you knew full well what you were doing."