Mandurah Detectives have charged a man after an incident in Secret Harbour on Sunday 19 May, 2019.
It will be alleged around 10:50am, the man was wearing a black cap with 'Police' embroidered on the front, and a lanyard with 'Security' written on the front.
It will be further alleged the man then asked two children to stop climbing trees in the park and advised he was a police officer.
The incident was reported to police and as a result of inquiries, a 77-year-old man from Golden Bay has been charged with one count of impersonating a public officer.
He will appear in court at a later date.