MELBOURNE(AFP) - A three-month-old baby has become the fifth victim of a deadly car rampage in Australia's second-largest city that left four others fighting for their lives and dozens injured.

A 26-year-old man drove his car into pedestrians at a busy shopping strip in the heart of Melbourne on Friday, hitting numerous people and sending others running for cover.

The infant died in hospital on Saturday evening, Victoria Police said.

The four others killed were a 10-year-old girl, two men aged 25 and 33, and a 32-year-old woman.

Hospitals were treating 37 other people, including four with critical injuries.

The alleged driver, who was shot by police in the arm, remains in hospital under police guard and has yet to be questioned by investigators.

His mother said she was ashamed of her son's actions.

"I feel so ashamed and bad, you know," she told commercial broadcaster Channel Seven Saturday.

"I don't want to be known that I'm the mother," she said, adding: "Go to hell and die in hell." Investigators said the driver, who has yet to be named by police, allegedly stabbed his brother early Friday morning.

Police tried to intercept the car before it entered the city in the afternoon and he was seen driving in circles outside Melbourne's main train station.

Victoria Police Chief Commissioner Graham Ashton said Friday the incident was not linked to terrorism.

The driver had a history of family violence as well as mental health and drug-related issues, he added.