A woman has died and another is seriously injured after an alleged hit-run collision in Newcastle.

NSW Police have declared a critical incident investigation as they search for a driver following the crash in North Lambton just after 2.40am.

Authorities reportedly observed a Holden sedan being driven recklessly on Newcastle Road and chose not to engage in a pursuit due to safety concerns. The collision happened shortly after on the same road, as stated by police.

The Holden sedan collided with a Hyundai sedan further along Newcastle Road.

The passenger of the Hyundai, a woman believed to be in aged her 50s, died at the scene.

She is yet to be formally identified.

The driver, a 28-year-old woman, was taken to John Hunter Hospital in a serious condition.

The driver of the Holden allegedly fled the scene before police arrived.

Paramedics attended to two backseat passengers in the Holden—a 15-year-old girl and a 17-year-old girl—before they were transported to John Hunter Hospital under police supervision.

A crime scene was created, and a critical incident team from the Hunter Valley Police District will be examining the circumstances of the event.

The investigation will be reviewed by the Professional Standards Command and oversighted by the Law Enforcement Conduct Commission (LECC).