Police arrested a man and confiscated a knife from him after an incident in Civic about 12.30pm on Friday.
The 26-year-old man had allegedly been aggressive toward bystanders in the Canberra Centre and causing a disturbance.
Police were called to the corner of Bunda Street and Petrie Plaza, where they said the man refused to comply with police directions.
One witness reported a Taser was used to subdue the man, although police did not report this action.
The man was taken into custody and conveyed to the City Watch House.
Anyone who witnessed the incident is urged to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website, quoting reference 6710714. Information can be provided anonymously.