A 16-year-old girl has been left in a critical but stable condition after she was struck by an e-bike at Barrack Heights, south of Wollongong, on Sunday night. Police are investigating the circumstances of the collision and have arrested a 35-year-old man who allegedly tested positive for alcohol and drugs following the incident.

Emergency services were called to Shellharbour Road near Sunset Avenue at Barrack Heights at about 10:50pm on Sunday after reports that an e-bike had collided with a teenage pedestrian. Ambulance crews treated the girl at the scene before she was flown to St George Hospital in Sydney for further treatment. Police said her condition remained critical but stable.

The circumstances surrounding the collision are still being investigated. Police said a second e-bike rider was reportedly in the area at the time and left without stopping to assist. Investigators are now appealing for information that could help establish exactly what happened immediately before and after the collision.

The 35-year-old male rider who remained at the scene was spoken to by police. Officers administered a breath test, which allegedly returned a positive result. He was subsequently arrested and taken to Oak Flats Police Station.

Police allege a second breath test conducted at the station produced a reading of 0.135. Investigators also allege the man returned positive results for cocaine and methylamphetamine. Police said those samples will undergo further analysis as part of the investigation. No charges had been laid against the man at the time of the ABC report.

Crash investigators examined the scene and seized the e-bike for forensic testing. The examination is expected to help investigators establish factors including the movements of the people involved, the circumstances of the collision and whether any other factors contributed to the teenager's injuries.

Police are particularly interested in identifying the second e-bike rider who allegedly left the scene. Investigators have asked anyone who witnessed the collision, saw the riders before or after the incident, or has relevant dashcam or mobile-phone footage to contact police or Crime Stoppers.

The incident has also renewed attention on the safety risks faced by pedestrians and e-bike users on busy roads and suburban streets. E-bikes are increasingly common across Australian communities, but collisions involving pedestrians can result in serious injuries, particularly when they occur at night.

Authorities have not yet determined whether the alleged alcohol or drug readings played a role in the collision. Those matters remain part of the police investigation, and any future charges would be considered through the court process.

The investigation remains ongoing as police work to identify the second rider and establish the full circumstances of the crash. The injured teenager remains in hospital while investigators continue gathering evidence.