A 14-year-old boy found wandering along in the middle of the night has been reunited with his mother following an appeal from police to help identify him.

The boy was wearing pyjamas when officers discovered him on Wicks Lane in Kogarah, 14 kilometres south of Sydney, about 12.40am.

Police from St George Police Area Command searched the area with the boy, who suffers a medical condition, but were unable to find his parents or carers.

His mother was tracked down Saturday morning about 8am after a tense morning searching in and around her home.

He was described as being of Caucasian appearance, about 155cm tall, of a thin build, with short dark hair, pale complexion, and brown eyes.

He was wearing long grey pyjamas with 'Marvel' superhero characters on them.

The boy was not wearing shoes and has not been able to identify himself to officers or provide any clues about his identity or home address.

Anyone who can identify the child has been urged to contact St George Police on 02 85667499.