The deaths of two men have been declared critical incidents, with the conduct of attending police officers to go under the spotlight.

Both men died within a short time of one another on Tuesday morning following separate police responses across regional NSW.

The first involved a 59-year-old man who died of a self-inflicted wound after being pursued to property in the state’s north.

Officers were called to a Walgett property about 8pm on Monday following reports of a concern for the man’s welfare.

He was unable to be located and was ultimately traced to a separate property north the town.

The man drove off and collided with a police vehicle before a pursuit was called off for safety reasons.

About 8.30am on Tuesday, police attended a property north of Walgett following reports his vehicle had been sighted.

The 59-year-old was found with a firearm near a vehicle.

Specialist resources attended the scene and negotiators attempted to speak to the man.

A firearm was discharged just before 11am and, although officers treated the man for self-inflicted wounds, he could not be revived.

The second incident involved a police pursuit in the state’s south.

Police were patrolling the Mid-Western Highway at Rankins Springs, north of Griffith, when they sighted a Mitsubishi about 10.55am on Tuesday.

Officers attempted to stop the vehicle, which had South Australian number plates, and a pursuit was initiated.

The vehicle crossed onto the wrong side of the road and collided head on with another vehicle, police say.

The male Mitsubishi driver died at the scene while the female driver of the second vehicle was airlifted to hospital in serious but stable condition.

Crime scenes were established following both incidents, with investigations being led by critical incident teams.

Investigations will be reviewed by the Professional Standards Command, with oversight by the Law Enforcement Conduct Commission, and reports will be prepared for the coroner.