The Department of Conservation (DoC) described wilding conifers as invasive weeds "that threaten to permanently alter the unique landscapes that are only found in New Zealand".
"Without any control, they will form dense forests that have environmental consequences on our native ecosystems, use up scarce water, and alter iconic landscapes," DoC's website said.
Bayer CropScience Proprietary Limited applied to import or manufacture Method 240 SL.
The company said the new herbicide had fewer hazards, including much lower risks to people, with lower application rates than other herbicides currently used on wilding conifers.
The EPA decision-making committee imposed strict rules for how Method 240 SL could be packaged, labelled, stored, disposed of, transported, handled, and used, EPA's Hazardous Substances Applications Manager, Dr Lauren Fleury said.
"The committee considers that, with these controls in place, the risks to human health and the environment are negligible, while the benefits to ecosystems and landscapes threatened by wilding conifers will be significant."
The EPA committee received nine submissions on the application - three supported the application and six opposed it. A public hearing was held on May 18, 2022.
The EPA said it regulated chemicals and other dangerous goods and substances under the Hazardous Substances and New Organisms Act - and rules were set to safeguard people and the environment.
Read more about the decision on Method 240 SL on the EPA's website here.
