Ask why Roundup is still sitting on supermarket shelves alongside everyday grocery items and you’ll usually hear the same answer:
It’s approved.
Approved sounds reassuring. Like someone, somewhere, carefully examined all the evidence and made a considered decision.
But when did that happen? Who made the decision? And under what regulatory framework?
Those questions take us back more than 50 years.
| Year | What Happened |
|---|---|
| 1975 | Glyphosate first registered under New Zealand’s former pesticides regime |
| 1996 | HSNO Act introduces New Zealand’s modern hazardous substances framework |
| 2004 | Glyphosate-containing substances transferred into the HSNO framework |
| 2018 | Associate Environment Minister asks EPA to consider reassessment |
| 2021 | EPA issues public call for information |
| 2023 | ELI requests grounds to reassess glyphosate |
| 2024 | EPA decides grounds for reassessment do not exist |
| 2025 | High Court finds no reviewable error in EPA’s decision |
| 2026 | ELI withdraws its Court of Appeal challenge |
1975: Glyphosate Was Registered Under New Zealand’s Old Pesticides System
Glyphosate was first registered for use in New Zealand in 1975.
That date matters because it predates the regulatory system New Zealand relies on today.
There was no Environmental Protection Authority (EPA). There was no Hazardous Substances and New Organisms (HSNO) Act. Glyphosate entered the New Zealand market under an earlier pesticides regime, using the laws and regulatory processes of the time.
Whatever that original registration involved, it was not an assessment under today’s HSNO framework.
That framework did not yet exist.
So when we hear that glyphosate has been “approved” in New Zealand for decades, it is worth asking exactly what that approval history involved — and what has happened since.
1996: New Zealand Creates a New Hazardous Substances Framework
In 1996, Parliament passed the Hazardous Substances and New Organisms Act.
The HSNO Act established a new framework for managing hazardous substances in New Zealand, including approvals, hazard classifications, controls and processes for reassessing substances when specified grounds exist.
Glyphosate, however, was already here.
A number of glyphosate-containing substances were subsequently brought into the HSNO system through a transfer process in 2004.
This distinction is important.
The EPA says those substances were assessed during the transfer process, assigned hazard classifications and given rules controlling their use. Since then, applications to import or manufacture individual glyphosate-containing substances have also been assessed under HSNO.
So it would be wrong to say glyphosate has never been assessed under New Zealand’s modern regulatory framework.
But that leads to a different question.
Has glyphosate ever undergone a comprehensive reassessment under that framework, taking account of the evidence that has accumulated since its original approval?
The answer appears to be no.
Assessment, Transfer and Reassessment Are Not the Same Thing
This distinction can easily disappear in public discussion.
An individual glyphosate product can be assessed for approval.
Existing substances can be transferred into a new regulatory framework and assigned classifications and controls.
Regulators can review new research and decisions made overseas.
None of those processes is necessarily the same thing as a formal reassessment under the HSNO Act.
The EPA itself describes reassessment as a formal review of the rules controlling a substance already in use in New Zealand. Before such a reassessment can proceed, there must first be a decision that legal grounds for reassessment exist.
That distinction becomes particularly important when we look at what has happened with glyphosate.
2018–2024: Reassessment Is Considered — But Does Not Happen
It’s not as though the question has never been raised.
2018 — The Associate Minister for the Environment asked the EPA to consider whether glyphosate should be reassessed. A reassessment did not proceed.
2021 — The EPA issued a public call for information on glyphosate.
It received 465 responses from members of the public, professional users and suppliers. The EPA says the exercise helped it understand how glyphosate was being used in New Zealand, concerns about its effects and the possible consequences if it were no longer available.
But the call for information was not itself a formal reassessment.
The EPA subsequently said its analysis of the information received did not indicate evidence of new risks that would warrant one.
Then came another attempt.
2023: Environmental Law Initiative Asks for Grounds to Reassess
In September 2023, the Environmental Law Initiative (ELI) asked the EPA to determine whether grounds existed to reassess glyphosate and glyphosate-containing substances.
That wording matters too.
ELI was not yet applying for the reassessment itself.
Establishing grounds for reassessment is the legal gateway that must be passed before a formal reassessment can proceed.
ELI argued that significant new scientific information had become available about the effects of glyphosate and glyphosate-containing products.
The EPA considered the material submitted by ELI alongside other evidence, including findings from overseas regulators.
In July 2024, its decision-making committee determined that the legal grounds for reassessment had not been established.
So the process stopped before a reassessment began.
2025: The High Court Challenge
ELI challenged the EPA’s decision through judicial review.
In October 2025, the High Court found that ELI had not established a reviewable error in the EPA’s decision-making.
That finding is important — but so is understanding what the Court was deciding.
The case was a judicial review of the EPA’s decision that grounds for reassessment did not exist. It was not itself a scientific reassessment of glyphosate.
The Court considered whether the EPA had acted lawfully in reaching its decision. It rejected ELI’s arguments and found no reviewable error in the EPA’s approach.
ELI appealed the judgment to the Court of Appeal in November 2025 but withdrew that appeal in May 2026.
The EPA’s decision therefore stands.
And glyphosate still has not gone through the formal reassessment process that the dispute was about.
What Does the EPA Say Today?
The EPA’s position is clear.
It says the existing rules governing glyphosate and glyphosate-containing products are sufficient to manage potential risks to human health and the environment.
It also says it agrees with most comparable overseas regulatory bodies that glyphosate is unlikely to cause cancer and can be used safely when the rules are followed.
The EPA says it monitors international developments and reviews new research relevant to New Zealand.
Those are important parts of the regulatory picture.
But they still leave an interesting question.
If the evidence supports continued approval, why not conduct a comprehensive modern reassessment and demonstrate it?
What Are We Actually Relying On?
More than five decades have passed since glyphosate was first registered in New Zealand.
During that time, New Zealand created an entirely new hazardous-substances framework.
Scientific knowledge has advanced dramatically, including continuing research into glyphosate’s potential biological effects.
Thousands of studies concerning glyphosate and glyphosate-based herbicides have been published.
International scientific and regulatory bodies have examined the evidence and, in some cases, reached different conclusions about particular hazards.
New Zealand Ministers have raised the question of reassessment.
The EPA has sought information from the public.
An environmental organisation has attempted to trigger the statutory reassessment process.
The issue has reached the High Court.
And yet a comprehensive formal reassessment of glyphosate under New Zealand’s modern regulatory framework still has not occurred.
That does not prove glyphosate is unsafe.
Nor does the absence of a reassessment mean that the EPA has ignored glyphosate for 50 years. It hasn’t. Products have been assessed, controls have been imposed, evidence has been considered and overseas regulatory decisions have been reviewed.
But neither of those facts answers the question many New Zealanders may reasonably assume has already been answered:
When was glyphosate comprehensively reassessed under New Zealand’s modern hazardous-substances framework?
Why This Matters for Public Confidence
Ultimately, this isn’t simply a debate about glyphosate.
It’s about confidence in the regulatory system.
When consumers see a weedkiller for sale in a supermarket or hardware store, they may reasonably assume its continued approval rests on a contemporary assessment of the accumulated evidence.
Perhaps that evidence supports exactly the regulatory position New Zealand has today.
If so, a comprehensive reassessment should provide an opportunity to demonstrate that.
And if the evidence points to changes in classifications, controls or conditions of use, the public should know that too.
Science earns confidence by continuing to test evidence. Regulation earns confidence by showing clearly how that evidence has been considered.
After more than 50 years of glyphosate use in New Zealand, the question isn’t whether regulators have ever looked at glyphosate.
They clearly have.
The more interesting question is:
Why, after more than 50 years of use, has New Zealand not put glyphosate through the comprehensive reassessment process its modern hazardous-substances law provides?
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