About 8.15pm, police activated sirens in an attempt to stop a vehicle travelling on the Mitchell Highway, Maryvale, about 40km south east of Dubbo.

A short time later, police located the vehicle on the same road, crashed into a pole.

A female passenger in the vehicle died at the scene. The male driver of the vehicle has been taken to Dubbo Hospital. His injuries are unknown at this stage.

A critical incident team will now investigate all circumstances surrounding the incident.

That investigation will be overseen by the Professional Standards Command.

All information will be provided to the Coroner.

As inquiries are in the early stages, no further details are available at this time; however, police are appealing for witnesses to come forward.

Police are urging anyone with information in relation to this incident to call Crime Stoppers on 1800 333 000 or use the Crime Stoppers online reporting page. Information you provide will be treated in the strictest of confidence. We remind people they should not report crime information via our Facebook and Twitter pages.

UPDATE: The road has now opened.