An Adelaide man visiting Sydney has been charged with allegedly carjacking a Mazda and driving erratically down George Street, hitting a pedestrian and crashing into a police car in front of stunned Thursday-night shoppers.

Johnny Starri, 36, was covered in blood and dressed only in his underwear when he was arrested outside the Queen Victoria Building about 9pm on Thursday, shocking onlookers leaving work and taking part in late-night shopping.

Starri allegedly bundled a 26-year-old woman out of her Mazda sedan after approaching the parked car at the intersection of King and Pitt streets in Sydney’s CBD, climbing over the roof and bonnet before throwing out the driver.

Police believe it was a random attack, and had fielded calls about the man’s erratic behaviour before the alleged carjacking. Detectives are investigating whether he was affected by drugs at the time of the crash.

Starri allegedly drove along George Street before crashing into a ride-share vehicle near the intersection of Market Street, hitting the driver, 27, and female passenger, 24. Both were unharmed.

The ride-share car then crashed into a marked police car parked near the light rail tracks at the Queen Victoria Building, occupied by two officers uninjured in the collision. The officers arrested Starri, who was treated by police and paramedics on the nearby footpath. Footage from the scene shows the car crashed head-on with the police vehicle, next to the light rail stop, while onlookers gathered.

A woman walking past the Queen Victoria Building was struck in the head by a bollard, which was dislodged from the ground after it was smashed by the Mazda, allegedly driven by Starri. The woman, who had been shopping at the precinct before the crash, was hospitalised in a stable condition.

Starri is known to SA Police but not NSW law enforcement. Police believe he was in Sydney on a brief visit, and are investigating the circumstances of his travel. He was taken to St Vincent’s Hospital under police guard, where he has undergone drug and alcohol testing.

Starri was charged with assault with intent to take the car, negligent driving, common assault, and destroy or damage property. He appeared in court from his hospital bedside on Friday, where he was refused bail to appear at Downing Centre Local Court on Wednesday.

Sydney City Police Area Commander Adam Solah described a “chaotic scene” confronting officers, and praised first responders at the scene.

“There were people out, late-night shopping outside the Queen Victoria Building. It was very crowded, we were very lucky that no one was seriously injured,” Solah said. “A number of bystanders came in to offer medical assistance to everyone who was involved, and they did a really good job.”

The police car parked on George Street is regularly stationed by the QVB for officers conducting proactive patrols, who are tasked with assisting the flow of traffic in the busy pedestrian area.

The woman allegedly bundled from her car was shaken by the incident, Solah said, and was helping police with the investigation. The scene has been cleared, and the light rail is running at normal servicing on Friday.

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Daniel Lo Surdo is a breaking news reporter for The Sydney Morning Herald. He previously helmed the national news live blog for The Sydney Morning Herald and The Age.Connect via email.