The controversial operation, reportedly carried out by the environmental group Matuku Link, involves the aerial application of glyphosate formulations to kill willow trees within a sensitive wetland ecosystem in West Auckland.
The wetlands of Te Henga are recognised habitat for critically endangered species, including bats and nationally significant bird populations such as the Australasian bittern. Wetlands also represent some of the most ecologically sensitive environments in New Zealand, making the use of agrichemicals in such areas particularly contentious.
Recent documentation reviewed by No More Glyphosate NZ raises serious questions about whether adequate environmental safeguards and community consultation have taken place.
Chemical risks in wetland environments
Technical analysis of the operation indicates that the herbicide Polaris 450, a glyphosate-based product, was reportedly used alongside Aquakynde, an additional surfactant designed to increase herbicide penetration.
According to product safety data sheets and regulatory classifications:
- Polaris 450 is classified as harmful if inhaled, causing serious eye irritation, and toxic to aquatic life with long-lasting effects.
- Aquakynde surfactants are associated with serious eye damage and aquatic toxicity, with documented impacts on aquatic organisms at very low concentrations.
Importantly, the safety documentation for Polaris 450 explicitly warns users not to allow the product to enter waterways.
Yet wetlands, by their very nature, consist of interconnected pools, saturated soils, and slow-moving water systems that can facilitate chemical movement and persistence.
When glyphosate formulations are combined with additional surfactants, studies show the aquatic toxicity of the mixture can increase significantly, particularly affecting amphibians, aquatic invertebrates, and early life stages of wildlife.
Compliance questions remain unanswered
Independent technical review has highlighted that spraying herbicides in or near standing water in wetlands creates high-risk exposure pathways through spray drift, wash-off, and sediment binding.
Under New Zealand’s hazardous substances framework, agrichemicals with aquatic toxicity classifications are normally prohibited from being applied directly into water unless stringent additional controls are met.
Regional planning rules, including the Auckland Unitary Plan (Chapter E34 – Agrichemicals), require agrichemical spraying to avoid spray drift into “sensitive areas” such as water bodies and wetlands, requiring strict management of spray drift, operator competence, and environmental safeguards.
In complex wetland systems like Te Henga, experts note that preventing herbicide movement beyond the spray site can be extremely difficult.
No More Glyphosate NZ believes the public deserves clear answers to several critical questions:
- What independent monitoring has been undertaken to assess environmental impacts?
- Has baseline and post-spray water or sediment testing been conducted for glyphosate and its breakdown product AMPA?
- What monitoring has been undertaken to protect endangered wildlife species in the spray area?
- What safeguards were implemented to prevent spray drift affecting nearby residents, wildlife, and waterways?
- Were local residents adequately informed prior to spraying?
- How were concerns from community members and environmental groups addressed?
Community trust at stake
Reports indicate that members of the local community have raised concerns with Auckland Council and environmental organisations for over a year, including meetings with council officials and submissions providing scientific data on wildlife impacts.
Despite this, the recent spraying reportedly proceeded while legal action was being pursued to halt the operation.
For many residents, the issue goes beyond the control of invasive willow trees.
It raises deeper concerns about public accountability, environmental stewardship, and the use of toxic herbicides in sensitive ecosystems.
A call for precaution and transparency
No More Glyphosate NZ is calling for:
- An immediate pause on herbicide spraying in the Te Henga wetlands
- An independent compliance and environmental review of the spraying operations
- Full disclosure of monitoring data, environmental assessments, and operational plans
- Genuine community consultation and transparency before any further spraying is considered.
“Wetlands are among the most fragile ecosystems we have,” said a spokesperson for No More Glyphosate NZ.
“When chemicals classified as toxic to aquatic life are sprayed in these environments, the burden of proof must be extremely high that no harm will occur.”
“Right now, the public simply doesn’t have enough information to be confident that this standard has been met.”
Until those questions are answered, the organisation believes the precautionary principle should apply.
“This is not an emergency situation. Taking the time to ensure environmental safeguards and community concerns are properly addressed should be the responsible course of action.”
About No More Glyphosate NZ
No More Glyphosate NZ is an independent public-interest initiative advocating for greater transparency, safer weed management practices, and reduced reliance on glyphosate-based herbicides in New Zealand.
The organisation works with communities, researchers, and environmental advocates to promote evidence-based decision making and protect public and ecological health.
