Auckland Council is disappointed people are ignoring bylaws and increasing the risk of spreading kauri dieback.
Last weekend 15 people were trespassed for entering closed areas of the Waitakere Ranges. Another 106 people have been trespassed previously.
"For the most part, Aucklanders, New Zealanders, even our tourists are all doing the right thing and staying out of the closed areas," regulatory compliance manager Steve Pearce told Newshub.
"Unfortunately we are finding people who clearly think the rules don't apply to them."
Most of the ranges' 144 tracks have been shut for more than two years.
Auckland Mayor Phil Goff said the closures are in place for a reason - to protect ancient trees for future generations.
"It's really disappointing that people are acting selfishly without regard to the permanent harm they may cause to our iconic kauri trees."
Pearce says no-go tracks are clearly sign-posted and fenced off.
"The places that are closed are closed to try and prevent the spread of the disease. Kauri dieback is a disease in the roots and soil... and if we can prevent that being spread to places where it's currently not, by stopping people going where it currently is, that's the best way that we can prevent it from being spread around the country."
Dieback has no cure, and can be spread on people's shoes. Even in areas not known to have the disease, visitors are required to wash their footwear just in case.
"Once a tree has the disease, it might take a few years, but it's on its last legs unfortunately," said Pearce.
Offenders face penalties of up to $20,000, and despite Auckland being at pandemic alert level 3, compliance officers are out and about trying to snap rule-breakers.
"If you do see something that doesn't look quite right, feel free to give the council a call," said Pearce.
Despite some work being halted due to the level 4 lockdown earlier this year, Auckland Council hopes to reopen some tracks by the end of the year. Eleven were reopened in 2019 and seven the year before, Stuff reported earlier this month.
"We're spending time and money getting those up to standard so that we can open up again and get people back into the Waitakere Ranges," said Pearce.