Police say on-duty officers shot a man threatening them with a knife in the early hours of Saturday on the state's central coast.
About 12.30am, police patrolling Watts Street - a block away from Gosford Station and a few blocks east of Gosford Hospital - were allegedly confronted by a man wielding a knife in a carpark.
The 20-year-old man was shot.
He was assisted by police before paramedics arrived to take him to Gosford Hospital. He is in a critical condition.
A critical incident team from Tuggerah Lakes Local Area Command will now investigate the circumstances surrounding the shooting. The investigation will be overseen by the Professional Standards Command.
Police are appealing for any witnesses to contact Crime Stoppers on 1800 333 000.