Walkers and cyclists on push bikes are being put at risk being knocked down and suffering serious injury by youths on electric bikes on the River Leven towpath between Dumbarton and Balloch.
There have also been reports of riders on racing bikes training for the UCI World Cycling Championships travelling at speed on the towpath near Balloch.
Police Scotland told The Democrat: “We have received reports of unregistered electric motorcycles without pedals being used on the grounds of Balloch Park, Cameron House and the length of the River Leven cycle track from Balloch to Renton.
“These are powerful battery-powered motorbikes capable of travelling in excess of 45 miles per hour.
“Riding these bikes poses a significant risk of harm to the rider and members of the public.
“As they are electrically powered, they are almost silent. Approaching and overtaking people from behind at speed on the River Leven cycle track in particular, is dangerous.
“These electric motorcycles require to be fully registered.
“Once registered, you must have a full driver’s licence, and a suitable insurance policy covering that particular motorcycle, and the bike must be taxed.
“If that is not in place, the only place where these motorcycles can be legally used is on private land with the landowner’s authority.”
The police have asked the public to report in confidence via 101 if they have any information regarding those involved.
Alternatively, people can email the Community Policing Team direct at ArgyllDunbartonshireCPTAlexandria@scotland.police.uk.