ACT Policing charged a 23-year-old man over an aggravated robbery at the Kaleen Caltex service station last month, which involved the use of a cross-bar tyre iron in an unprovoked attack on a staffer.

The man will face the ACT Magistrates Court today.

The incident was one of the 21 armed robberies reported throughout the past 10 weeks in the ACT.

Detective Sergeant Craig Marriott said there had been an increase in reports, but the recent rate was lower than the same period in 2011, which recorded 23 incidents.

At least 12 of the recent aggravated robberies involved a knife, which Detective Sergeant Marriott described as the weapon of choice as they are easily accessible and ''virtually impossible'' to regulate.

''When we talk about the legal restriction on a sale, people usually think about the hunting style knife and even pocketknives,'' he said. ''But often the description we're given by victims is the kitchen knife, the carving knife, which is readily available in most households.''

Detective Sergeant Marriott said police believed some of the recent offences were linked, but would not disclose any further information.

He urged locals to put their safety first if involved in an aggravated robbery and comply with the demands of the offenders, which he said were usually desperate or drug-fuelled.

In urging compliance, Detective Sergeant Marriott referred to the failed armed robbery of the Latham Post Office in 2003, which resulted in one man dead and others injured after they attempted to stop the would-be thief.

He said offenders usually targeted places with easy escape routes, such as liquor stores and service stations, and said these businesses should take precautions including automatic door locking mechanisms and good lighting.

''They can't guarantee that the business won't be subject to an armed robbery but what it does is reduce the attractiveness of the location to offenders,'' he said.

ACT Policing is seeking help from the public to prevent further aggravated robberies, and are asking people to call Crime Stoppers if they notice people acting suspiciously, loitering unnecessarily or cars parked at strange times of day or night.

Detective Sergeant Marriott also appealed to the friends and family of recent offenders.

''Somebody is going to have some information regarding these offences of late and have either direct knowledge or suspicions of who these offenders are,'' he said. ''We'd really like to call on those people to please, search your conscience and pass on that information to us.''

Anyone wishing to provide information about the recent robberies can contact Crimes Stoppers on 1800 333 000 or via the website.