St Marys: Great Western Highway closed after police incident leaves one dead and another on the run in Sydney

One of Sydney’s main highways has been closed in both directions after a major crash left one person dead and another on the run from police.

A critical incident investigation has been announced after a man died in a crash in St Marys.

At around 4am on Tuesday, two officers in a fully marked police car saw a dark gray Holden Insignia sedan stopped on Mamre Road in St Marys.

Police stopped near the sedan when the driver allegedly accelerated towards the Great Western Highway, where police lost sight of the vehicle.

Police followed and found that the sedan had crashed into a silver Toyota Corolla hatchback. The driver of the sedan then allegedly fled the scene on foot.

The driver of the hatchback died at the scene; his identity has not yet been established, but he is believed to be about 40 years old.

A short time later, a 43-year-old man, believed to be the driver of the sedan, was arrested on Chapel Street.

He was taken to Nepean Hospital under police guard for mandatory testing.

A crime scene has been established and the incident is being investigated by the Northern Coast Police Command Incident Team. The investigation will also be subject to independent review.

Anyone with dashcam footage, CCTV footage or information about the incident is urged to contact police or Crime Stoppers on 1800 333 000.

The Great Western Highway is closed in both directions at St Marys, between Glossop Street and Sydney Street.

Cars are routed through Glossop Street, Brisbane Street and Sydney Street in both directions. Heavy vehicles can use the Mamre road, M4 and M7. Drivers should check www.livetraffic.com for updates.