"The vast majority of Aucklanders understand that staying off closed walking tracks is necessary to keep our kauri trees safe from dieback disease," he said.
"I hope this fine acts as a warning to those few people who repeatedly ignore the rules and put our iconic kauri trees at risk. This is not acceptable and will not be tolerated."
Gojack had entered closed areas of the Waitākere Ranges Regional Park and was issued with a trespass notice first in September 2019 then again in March and July of 2020.
He was found via CCTV to have re-offended in April and again in June 2020, walking on the Karamatura Valley Track in breach of a trespass notice.
Two charges for breaching the Public Safety & Nuisance Bylaw were filed with the court.
Environment and Climate Committee chair Councillor Richard Hills says prosecution is always a last resort, but "to protect our native taonga we need to use every tool at our disposal".
"We are aware how tough it is for some communities with the loss of access to our native forests, that's why we are putting significant investment into safe track upgrades and new kauri hygiene stations that will enable access, while protecting that access for future generations."
Gojack, who represented himself, asked the court to consider a sentence of voluntary work in lieu of a fine due to his financial circumstances.
As the offence is fineable only, the Judge was not able to consider a community-based sentence.
Judge Tremewan noted the effort council had made to work with the defendant to ensure he understood the closure and the obligations of his trespass notices, but he had failed to do so.
Judge Tremewan said that a stiff financial penalty was appropriate and should reflect the need to set a level that would not be a mere "licencing fee" but would deter both the defendant and others from breaching the bylaw.
Signs displayed outside the closed tracks say: "Stop, do not enter. Strictly no access.
"Any unauthorised person entering this closed area commits an offence."
"Penalties up to $20,000."
Tree killing disease
Goff last year said these prosecutions 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."
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.
The closure meant people entering those tracks could be prosecuted under the council bylaw.
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.