The apparent attempted theft of two water tanks from an environmental group turned violent when the alleged thief was confronted on camera.
Friends of Okura Bush volunteer Geoff Reid was swung at and shoved when he confronted the man on Tuesday afternoon.
The environmentalist also had a piece of timber hurled at him as the man tried to flee.
Reid told 1News he returned from controlling moth plant and Japanese honeysuckle in the bush "just in time" to find a man had loaded some of the group's water tanks onto his trailer.
The plastic water tanks are used by the group to store water for native plants and to mix herbicide to control invasive plant species and weeds.
On video of the incident taken by Reid, the man claims "the containers aren't yours", saying he knows the owner.
He also claimed the land the tanks are on is public land.
"I would like you to put them back please," Reid can be heard asking a few times.
The man eventually shoves the tanks off his trailer and onto the ground before moving to leave the scene.
He becomes violent as he moves towards his ute, swearing at Reid and moving to swing at him a few times.
Reid can be heard saying, "you're violent and you're a thief" as the man climbs into his ute, shoving Reid as he does so.
The video later shows the man stopping his ute to grab a piece of timber out of the tray, hurling it at Reid. It hits the side of a nearby car.
Reid said although it was "rewarding to catch someone in broad daylight", it was "disheartening" and "frustrating" to see the man allegedly stealing from the group.
"The community put a lot of effort in to keep this very special part of the environment alive and flourishing and with the little funds we get it's very challenging when we have thieves in the community."
Okura Bush is one of the last stands of sub-tropical broadleaf coastal forest, Reid said, describing it as an important "slice of identity and heritage".
The bush also contains kauri trees and a rāhui has been in place since May 2018.
With a lot of volunteers like himself looking after the area, Reid said he wanted people to feel safe while they were protecting the environment.
He told 1News he had given police the man's licence plate number and the footage of the incident.
Reid also shared the footage to Instagram, Reddit and YouTube in the hope of identifying the man.
Police said they are investigating.
A spokesperson said they spoke with Reid at the time and tried to locate the vehicle involved.
The spokesperson said they are aware of Reid's footage and are making "further inquiries" into the incident.
Anyone with information can call police on 105, quoting file number 220511/9121.