Police are appealing for public assistance to locate Christian Hargrave-McKey who was last seen at about 8am on Thursday, April 4 at Woy Woy railway station.
When the 35 year old was not able to be located or contacted, he was reported missing to officers attached to Brisbane Water Police District, who commenced inquiries to locate him.
Police hold serious concerns for his welfare.
Hargrave-McKey is described as being of Caucasian appearance, about 170cm tall, medium build, with brown hair and a scar on his chest.
Anyone with information in relation to his whereabouts is urged to contact Brisbane Water Police or Crime Stoppers on 1800 333 000 or online at nsw.crimestoppers.com.au