The incident occurred on Saturday December 17 last year at around at 5.30am when a man in his 20s was walking home through Queens Square in the city centre.
He was approached by a group of men, one of whom punched him in the face. The victim was then pushed to the floor and told to hand over his mobile phone. The men took the phone and left.
The victim – who required surgery to treat his injuries – has been left traumatised by the incident.
Now police are appealing for help to identify the men in the CCTV footage, who officers believe will be able to help with their enquiries.
The men in the CCTV footage, or anyone who recognises them, should contact police on the non-emergency number 101. Alternatively, call Crimestoppers in confidence on 0800 555111.