Police investigations are continuing into a triple stabbing in Whalan last night (Wednesday).

Detectives will address the media at Mt Druitt police station this morning after a man died and two others were injured. It is believed two of the men were father and son.

About 7.30pm (Wednesday 22 December), emergency services were called to a reserve at Catlin Close, Whalan, following reports of a stabbing.

Upon arrival, officers attached to Mt Druitt Police Area Command located three men – aged 40, 25 and 19 – suffering stab wounds.

Despite the efforts of emergency services, the 40-year-old man died at the scene.

The two injured men were treated by NSW Ambulance paramedics at the scene before being taken to Westmead Hospital for treatment.

The younger man was in a critical condition with injuries to his torso and arm.

The older man was in a stable condition with a laceration to his arm.

All three men were known to each other.

Officers established a crime scene and commenced a coordinated search of the area, with assistance from Nepean Police Area Command, PolAir and the Dog Unit.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000.