Police fear for the safety of a teenage boy who has been missing from his Mosman home since Sunday.

Justin Painter, 15, was last seen at his house on Mosman Street about midday. He has not made contact with friends or family since.

Justin Painter catches a ferry from Mosman, shortly after he went missing.

His disappearance is said to be out of character.

Police say he boarded a ferry at Mosman shortly after he went missing.