Householders in Co Galway have been warned not to have any dealings with bogus waste collectors, who call to their homes offering to clean out garages and remove old washing machines and fridges.
Those who use the bogus collectors could end up before the courts, and face fines of up to €1,900 or 12-month jail terms, if the contents are traced back to them from illegal landfill sites.
Galway County Council is understood to be on the trail of six gangs - three from the city, and one each from the Tuam, Athenry and Portumna areas - which have been operating illegal waste-collection businesses for some time.
The problem has increased significantly over the past few years, particularly in the quiet bog road areas on the Headford Road.
The dumpers originally used small advertisements in local newspapers but, more recently, have resorted to distributing flyers in housing estates, containing just a mobile phone number and a person's first name.
Those who operate waste-collection services can no longer advertise in newspapers without displaying a valid waste permit reference number. They must have a Waste Collection Permit.