Reassessment of diazinon, fenamiphos and methamidophos


The decision has been made on the modified reassessment of diazinon, fenamiphos, and methamidophos, and the decision is published.

The decision-making committee has revised the expiry of the time-limited approvals for the organophosphate pesticides methamidophos and fenamiphos, and declined the application to extend the approval timeframes for diazinon:

  • approvals for substances containing fenamiphos or methamidophos expire: 1 July 2024
  • the existing expiry date for diazinon approvals remains in place: 1 July 2028.

After the expiry date, these substances will no longer be able to be imported or manufactured in New Zealand.

The committee has recognised the importance of fenamiphos in biosecurity use. They consider that this use pattern presents lower risks than wide dispersal plant protection use patterns which they consider have higher risks compared to methamidophos plant protection products. Therefore, the committee decided to limit the use of fenamiphos during the extension period to biosecurity uses only. From 1 July 2023 the use of fenamiphos will only be permitted for biosecurity purposes in accordance with the Biosecurity Act 1993.

The decision considers protecting human health and the environment from the risks of ongoing use of diazinon, fenamiphos, or methamidophos. It also acknowledges the concerns from Māori and the wider public regarding the health and environmental effects of these substances, as well as the benefits provided by the use of these substances including the availability of alternative substances to replace them when the approvals expire.

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New Zealand EPA, 11-10-22