Police operating in the Brecon Beacons have instigated a zero tolerance policy against illegal off-roading along National Park trails.
Three drivers have already been prosecuted for illegal off-roading
The clamp down has been made after a rise of illegal off-road bikes and 4 by 4 vehicles at the national park this summer which are damaging the landscape.
And under new laws, offenders could have their vehicles confiscated by the police.
Last Sunday, two motorcyclists were stopped on the Taff Trail near Talybont-on-Usk and were given on the spot fixed penalty fines.
And in early August, three 4 by 4 drivers were prosecuted for using the Gap Road at Taff Fechan Forest near Brecon while it was closed.
This particular route is only open to vehicles during the months of March and September and the first two weeks of October.
The drivers were fined £50 and ordered to pay £35 costs.
"This clearly illustrates to everybody there will be zero tolerance shown to those who tear up the landscape and spoil the quiet enjoyment for others," said Chris Ledbury, head of countryside at the Brecon Beacons National Park (BBNP).
"There are designated places for off-road use in the national park, and people should contact us to find out where they are, and avoid breaking the law."
Off-road hot spots the BBNP has highlighted are at Hay Bluff above Hay-on-Wye, an area near Talgarth, Talybont and Taff Fechan near Talybont-on-Usk and a route on Mynydd Bach, near Talgarth.
The police are targeting off-roading hot spots in the Beacons
"We are particularly concerned about Mynydd Bach because the remains of a Roman Camp is sited there and off-road vehicles are causing a lot of damage to it," said Mr Ledbury.
Although two motorcyclists were caught on Sunday, there were another 13 motorcyclists in the group that police said escaped capture.
"These vehicles are causing significant erosion as well as disturbing walkers, cyclists horse riders and people who live in that area," said Mr Ledbury.
A Dyfed-Powys Police spokesman said: "From now on under the Police Reform Act, it is even possible that some offenders may have their vehicles confiscated."
Denis Cardell, prescient of the Welsh Association of Motor Clubs said : "The best way for people to avoid getting into trouble is to join a local motor club such as the Hill Rally Club.
"It is a shame that these people don't know enough about motoring to do this."