Police in Bolton have received increased reports of bikers up on the hill and are now taking targeted action.
Section 59 warning signs, relating to the use of off road vehicles, have now been placed at access points leading to the moorland surrounding winter hill mast.
It's been reported off-road bikers are using the land without permission and are even breaking down new gates and fences to gain access.
Posting the warning online officers from GMP's Bolton North division said
"After this summer’s major fire incident, the area needs to recover. Off road vehicles have a direct negative impact on this process.
"There are also reports that individuals have broken and damaged new fencing and gates that replaced those destroyed during the fires to gain access.
"This is not acceptable. Off road bikes / vehicles are NOT welcome on the hill. Regular patrols are being conducted and should you be found using them in the warning area, they will be seized without further notice."