Visitors and locals have been asked to use greenlanes 'appropriately'.
It comes following reports of a group of off-road bikes riding over hill land from Snaefell Mines to the Veranda, over the Snaefell Mountain Railway tracks and towards Windy Corner during Monday’s racing.
In a joint statement from government, Police, the Auto-Cycle Union, and the Manx National Farmers Union - people have been urged not to ride away from designated tracks, on open hill land or disturb livestock/wildlife.
Riding an off-road motorbike or 4x4 away from marked greenlanes or public highways is an offence under section 28 of the Road Traffic Act.
Further, both the Forestry Act 1984 and the Wildlife Act 1990 may be used in relation to illegal access and disturbance of wildlife and habitats.
Those who are flout the rules could be fined, given points on their license or be prosecuted.
A separate group was also seen riding on Snaefell at the same time - officials say illegal riding of this nature causes damage to our local habitats, wildlife and disturbs livestock.
The Department of Environment, Food and Agriculture (DEFA) and the Police are making enquiries regarding the riders and photos circulating on social media.
If you would like to report any suspected illegal access, you're asked to contact either the Police on 631212 or the DEFA Ranger Team on 07624 205250.