Some tracks are to close in the Hunua Ranges - south east of Auckland - to protect kauri from a deadly fungus which can be spread on the footwear of walkers.
Kauri trees in the area appear to still be healthy, but Auckland Council is taking precautions to stop kauri dieback disease spreading to the area.
It's setting up protection zones, which will put parts of the ranges out of reach to the public.
The new measures start at the beginning of next month and will be reviewed after a year.
There will also be some re-routing of tracks, upgrades to walkways, and improved maintenance.
A similar initiative has already begun in the Waitakere Ranges Regional Park.