The manager of the Aldi store in Almancil was held hostage by two robbers as she arrived for work on Christmas Eve.
The incident took place at 7.30am when the victim was opening the door to the store.
She was held at gunpoint by the men, who forced her into the store and demanded access to cash.
Wearing balaclavas and gloves, the robbers locked the woman in an office and fled the scene with around €5,000 via one of the automatic glass entry doors, which they broke.
In possession of a spare key to the office, the store manager was able to free herself and call the police, who are now investigating the case.