Two men, one armed with a suspected firearm and one with a knife, escaped with cash from a business on the Woodburn Road in Carrickfergus, on Friday night (19 April).
The men entered at around 11.10pm and threatened a number of patrons and staff before making off with a sum of cash.
Police are investigating the incident.
It was reported that a white Hyundai car was stopped by police a short time later at Prince Andrew Way in the town, and a 30-year -old man was arrested on suspicion of robbery and possession of an offensive weapon.
The man armed with the suspected firearm was reported to have been wearing a light coloured tracksuit and a white puffa style jacket, black trainers, a black balaclava and gloves. The man carrying the knife was wearing a black tracksuit with a white and black balaclava and black gloves.
Efforts are ongoing to locate the second man believed to have been involved and anyone with any information about this incident or who may be able to help with the investigation, is asked to call detectives on the non-emergency number 101, quoting reference number 2072 19/04/24.
A report can be submitted online using the non-emergency reporting form via http://www.psni.police.uk/makeareport/ or you can also contact Crimestoppers anonymously on 0800 555 111 or online at http://crimestoppers-uk.org/.