Auckland Council is taking its first prosecution against a member of the public for walking on tracks in the Waitākere Ranges that are closed to prevent the spread of kauri dieback disease.
The bushwalker is facing three charges after entering a closed track in the ranges west of Auckland three times over the past five months.
Auckland Mayor Phil Goff said the prosecution was regrettable, but to be caught three times "just shows the sense of entitlement and total ignorance of the impact that that individual may have on spreading kauri dieback which is threatening to wipe out our iconic tree species".
He said the council was sending a message by taking the prosecution.
"Most people, they understand absolutely. We get complaints - 'Why are you closing the tracks?'. Well, we're not doing it for fun. We're doing it for a vital reason which is to protect the kauri tree and to stop the spread of this disease which will wipe it out.
"But some people just don't hear or just don't accept the message and the last resort is what we're doing here, taking a prosecution order and that may subject the individual of a fine up to $20,000, that's up to the court of course to impose what they think is appropriate."
Often, it was local people breaking the rules of the bylaw in the ranges - a key step in the halting of kauri dieback.
The major vector of the disease being spread was human beings, Mr Goff said.
If breaking the rules continued, the council would step up prosecutions, he said.
"Our obligation as a council ... is to our generations and future generations. And I want my kids and my grandkids to be able to walk those paths to see those kauri trees and not have that forest ... subject to the massive destruction that is going to take place."
There would be a zero tolerance approach from now on, he said.