Victims' families say Bourke Street killer James Gargasoulas' 46-year jail sentence isn't long enough for committing one of Australia's "worst examples of mass murder".
Garasoulas, 29, was sentenced on Friday to six life sentences for his "callous and cowardly" Melbourne driving rampage.
He will be eligible for parole in 2063, aged 73.
Victims' relatives filled Victoria's Supreme Court for the ruling and later said dangerous murderers like Gargasoulas "should never be allowed to roam freely".
"The sentence is not harsh enough," the families of five victims said in a joint statement.
"(We hope) no one will ever have to suffer a similar fate as those who lost their loved ones."
Their lawyer said some relatives felt very disappointed by the sentence but remained dignified throughout the hearing.
"Some feel that he shouldn't have been granted parole at all," said Genna Angelowitsch from Adviceline Injury Lawyers.
"They have a life sentence. They don't get parole from their grief."
Gargaoulas stood emotionless in the dock as he was sentenced.
"This was one of the worst examples of mass murder in Australian history," Justice Mark Weinberg said.
"Your actions were both callous and cowardly. You have shown no genuine remorse."
Gargasoulas used a stolen car to mow down and kill six people in the busy Bourke Street mall on January 20, 2017.
His victims included three-month-old Zachary Bryant, who was thrown 60 metres from his pram, and 10-year-old girl Thalia Hakin, who was holding her mother's hand when struck.
"By your deliberate and wanton conduct, you murdered six young people, none of whom you knew, and none of whom had done any wrong," the judge said.
Gargasoulas badly injured dozens of others in his "terrifying rampage", committed in a drug-induced psychosis.
"Your crimes have had a shattering effect on countless lives," Justice Weinberg said.
A sentence of life in jail without parole is rare but has been passed in Victoria, for serial killer Peter Dupas and torture killer Michael Cardamone.
In calculating Gargasoulas's sentence, Justice Weinberg considered mitigating factors, like his relatively young age and chronic psychosis.
"Your time in prison will be more onerous ... than it would for someone not suffering from your current mental illness," the judge said.
Gargasoulas was using "ice" in the weeks before the attack and was on bail, "ironically" meant to face court on the day of the massacre, the judge noted.
He launched a stabbing attack on his brother Angelo that morning.
Police tailed the stolen Holden Commodore in South Melbourne but gave up the chase for safety reasons prior to the CBD rampage.
Gargoulas was arrested at the scene and later pleaded not guilty to killing Zachary, Thalia, Jess Mudie, 22, Yosuke Kanno, 25, Matthew Si, 33, and Bhavita Patel, 33.
A jury in November found him guilty of the murders and 27 counts of reckless conduct endangering life.
The killer, who suffers treatment-resistant paranoid schizophrenia, was earlier found fit to stand trial.
In a letter read to the court, Gargasoulas insisted he was not evil and blamed "government oppression" for the murders.
He has also maintained he was the Messiah and had acted on the wishes of God, and believed a comet was looming in the sky.
Australian Associated Press