A person charged three times for entering tracks closed in the Waitākere Ranges due to kauri dieback could be fined up to $60,000.
Auckland mayor Phil Goff said the prosecution - the first of its kind following the unprecedented track closures - reflected the "seriousness of the issue".
"While most Aucklanders understand the need for temporary track closures to help stop the spread of dieback, those individuals who flout the rules with no regard for the damage they cause need to be held to account."
The Waitākere Ranges Regional Park has become a hotspot for the tree-killing kauri dieback disease, with a 2018 survey showing it had spread to around 20 per cent of kauri in only a decade.
In May 2018, Auckland Council closed high-risk tracks in the Waitākere Ranges Regional Park to the public to protect forested areas from the further spread of kauri dieback disease, after Auckland iwi Te Kawerau a Maki initiated the process by placing a rāhui, or ban, over the area.
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The closure meant people entering those tracks could prosecuted under the Public Safety and Nuisance Bylaw.
The three charges, filed in Waitākere District Court, were for a person who entered a closed track three times in the past five months.
They are scheduled to appear in court on January 6, 2020, with each charge subject to a fine of up to $20,000.
"The survival of our most iconic native tree is at risk and the decisions to close the tracks are based on hard evidence about what is necessary to slow and reverse the spread of kauri dieback disease," Goff said.
In the past six months, 49 trespass notices have been issued.
Auckland Council's regulatory compliance manager Steve Pearce said their officers were working to increase the level of education about the disease and compliant behaviour.
"Most Aucklanders have heard the message; they keep off closed tracks and use the cleaning stations so it's disappointing a few continue to believe the rules are not for them."
Compliance officers would be increasing their presence over the Christmas and New Year period in the Waitākere and Hunua Ranges and in local parks where tracks had been closed.
Ambassadors would also be out in force, educating visitors on kauri dieback, Pearce said.