The force said that the man was left concussed after the alleged attack, which was reported to have taken place in the area of David Place shortly before 1am on Saturday.
The first suspect has been described as a 16-year-old boy, of average build and around 5’9” tall, with dark brown and slightly curly hair that was short on the back and sides and longer on top.
He is said to have been wearing a black North Face jacket.
Another suspect is described as a 16-year-old boy with a slim, lanky build, about 5’10” with very short-cut light brown hair who was reportedly wearing “a greyish sweatshirt”.
A third suspect is described as a 16-year-old girl of average build, with shoulder length brown hair.
The force said that the alleged victim also suffered bleeding inside the ear, as well as bruising and abrasions.
“Numerous vehicles were in the area at the time,” the appeal continued.
CAN YOU HELP?
Anyone who may have seen the incident or who has any information is asked to contact the police on 612612 or the independent charity Crimestoppers anonymously on 0800 555 111, or via their anonymous online form here.