There were unconfirmed indications that at least one person carried out the robbery at the dairy in Elgin Rd at 8.40pm and there was a suggestion a firearm may have been involved.
Police confirmed there had been a robbery, but further details were not immediately available.
It was also not immediately clear if there was a link between this robbery, and an earlier incident in which masked offenders stole cigarettes from a South Dunedin dairy on Sunday night, the latest in a string of such incidents.
A police officer was guarding the Stadium Store in Victoria Rd on Sunday night after what police said was a theft, as no weapon had been used.
The incident occurred after a petrol drive-off at the Challenge Fitzroy service station in South Rd, Caversham, also on Sunday.
Station attendant Callum MacArthur said a person in a red Mazda had stolen petrol at 6.10pm. Police had told him it could be related to the theft.
A spokeswoman said police were investigating the reported theft at the Stadium Store about 7.30pm.
The two offenders wore masks and stole cigarettes before fleeing in a vehicle.
