Police are warning Ballina businesses and residents to check their cash after counterfeit $50 notes were detected circulating across the Richmond Police District.

Richmond Police District issued the community alert today, urging retail workers in particular to take extra care when accepting $50 notes.

Police say counterfeit notes can often feel different from genuine Australian currency and may be missing key security features.

Business owners are being encouraged to make sure staff know what to look for, particularly during busy trading periods when cash may be handled quickly.

Anyone who suspects they have received a counterfeit note should handle it as little as possible and place it safely in an envelope.

Police recommend recording as much information as possible about how the note was received, including the date and time, a description of the person involved and their clothing, vehicle details and registration numbers, and whether CCTV footage may be available.

The suspected counterfeit note should then be reported immediately to a local police station.

The Reserve Bank recommends people who are unsure about a banknote compare it with one they know is genuine and check its security features.

Police are also seeking information about anyone using or distributing counterfeit currency across the Richmond Police District.

Anyone with information can contact local police or Crime Stoppers on 1800 333 000.