A man was walking along Chandler Street in Belconnen with a black handgun allegedly pointing it at buildings, cars and several members of the public at about 8.30 on Monday morning.

A short time later, police arrested a 43-year-old Belconnen man, who had a replica handgun on him.

They charged him with acting to cause public alarm and unauthorised possession of a prohibited firearm.

Police are looking for witnesses to the incident around Chandler Street and Swanson Street between 8.30am to 8.40am.

Contact Crime Stoppers via the Crime Stoppers ACT website or call 1800 333000.