It's the latest in a spate of robberies across Canberra in less than three weeks, including two men who threatened customers and staff at a Woden supermarket last week.

The man entered the The Barrow on the ground level of the Waldorf building at the corner of Akuna Street and London Circuit about 5.45pm.

The man threatened an employee with a large knife and demanded cash. The staff member handed over the money and the man fled on foot.

Police say the man was wearing a black hooded jumper and a covering over his face. The black jumper featured grey sleeves and a large grey design on the front.

ACT Policing is investigating the aggravated robbery and seeking CCTV footage.

The Barrow robbery comes after two men armed with knives robbed the Hughes IGA on May 24, two days after another man with a knife stole cash from the Kaleen Caltex service station.

Meanwhile, two men armed with wooden poles robbed a Tuggeranong home and assaulted its resident on May 17.

Police are urging anyone who may have witnessed the incident or has any information that could assist police to contact Crime Stoppers on 1800 333 000 or via act.crimestoppers.com.au

Information can be provided anonymously.