At around 7 am on Friday morning, a male armed with a knife entered the shop and threatened two female staff members.
He made off with a quantity of cigarettes in a red recycling box and headed on foot in the direction of Willowfield Walk.
Police say he wore a mask and a red hooded top.
The two female staff members, both aged in their 20s, were not injured in the robbery but were left shaken.
Detective Constable Gareth Hussey said: “I would ask anyone with any information about this incident to contact detectives in Musgrave Police Station on the non emergency number 101.
“Or if someone would prefer to provide information without giving their details, they can contact the independent charity Crimestoppers and speak to them anonymously on 0800 555 111.”