The Alborns skink is part of the speckled skink family and is only found at one site near Reefton close to Big River, which is off-limits to vehicles.
Monitoring since 2015 has only detected 17 individuals, therefore the population is considered extremely vulnerable to extinction.
Four-wheel drivers have recently turned part of the site into a mud hole and driven over skink monitoring pit covers, which could have crushed and killed skinks.
Trees have also been illegally cut down to make new tracks, destroying the homes of the at-risk forest gecko.
DOC Senior Heritage and Visitor Asset Ranger Sam Symonds says the damage is thought to be related to an ongoing issue of vandalism in the area, with continued destruction of assets and vegetation at the Big River Hut and Mine site.
“On average DOC spends around $20,000 each year repairing damage from what is thought to be just a small number of people, and we’d like to stop them.