The man had been driving when he is alleged to have reacted violently when his passenger changed the car radio station and crashed the car.
Cronulla NRL club chairman Steve Mace, who saw the incident unfold, lauded a fellow passer-by who intervened and put himself between the woman and the allegedly knife-wielding driver despite suffering a serious stab wound.
A man allegedly stabbed his partner while in their car on a major highway before turning on those who came to her rescue.
“Getting her in and out of that car to dodge the stab wounds was unbelievable,” Mace told Sydney radio 2GB on Monday.
Video from witnesses shows a man holding the passenger door shut as a man, with blood across his white shirt, moves about the rear of the car, shouting.
“The first time you were dodging swings, like deadset swings, and all he was carrying on was about a radio station getting changed,” Mace said.
“Then it was ‘you’re all gone anyway because you’ve all got the jab’.’”
The woman reportedly needed to be calmed after she saw her partner run up the street when police arrived.
“All she was worried about was him and what the police were doing to him,” Mace said.
The woman and her helper remain in hospital, but both improved overnight to a stable condition.
The driver was known to police but not for domestic-violence matters involving the woman, police said.
A police officer was also seriously injured while arresting the driver, while two people were injured in the crash.
NSW Premier Chris Minns credited the “incredibly brave” people who intervened during the incident.
I want to thank the brave NSW Police officers, first responders and members of the public for their actions.
We are thinking of those innocent people who have been injured.
He noted a “cruel irony” in the alleged domestic violence-related incident occurring as NSW Police ran a major operation targeting the crimes at the weekend, arresting 550 people.