A large-scale police operation is underway in Sydney's south with at least one person stabbed in the stomach and another person presumed dead.
Emergency crews were called to West Botany Street in Rockdale after 3pm on Friday following reports of a multiple vehicle crash.
A 20-year-old man has been stabbed in the stomach, authorities say.
A witness, who wished not to be identified, was working at a business nearby when people in shock were brought into the building.
The witness said police and other onlookers told her a truck had run into cars before the driver car-jacked a red taxi and fled.
NSW Police and NSW Ambulance have multiple crews in the area and there are reports of other incidents nearby which could be related.
An AAP reporter said there were a number of police cars on Forest Road near St Francis Xavier's Catholic Primary School in nearby Arncliffe. There was a white sheet on the ground at the scene.
AAP understands the Arncliffe incident is self-harm and related to the Rockdale incident.
West Botany Street remains taped off and police are interviewing people at the scene.
