Officials have found grounds to reassess approvals of substances containing a controversial group of insecticides linked to declines in honeybee populations.

Neonicotinoids are used extensively to protect crops here and overseas, and many have systemic effects on plants, meaning treating the seeds with them can leave a plant protected throughout its life.

They've largely replaced problematic insecticides used in the past, such as organophosphates and DDT, although in light of concerns over their environmental impact, major retailers including Placemakers, The Warehouse and Bunnings Warehouse have taken them off the shelves.

Current New Zealand rules around neonicotinoids include not spraying insecticides close to bee hives or crops with budding or flowering plants where bees may gather and feed.


California bans controversial Chlorpyrifos pesticide spray
Dr Jacqueline Rowarth: Is organic food chemical-free?
Niki Bezzant: Should we be worried about pesticides in our food?
Banned pesticide DDT Muster gathers pace

That could now be about to change, with the Environmental Protection Authority (EPA) this week announcing there was reason to review the rules controlling the substance – although the agency stressed this was just a first step.

The EPA determined there was grounds for a reassessment after reviewing new information from overseas agencies, including the European Food Safety Authority.

The EPA's hazardous substances and new organisms acting general manager, Gayle Holmes, said a reassessment would be a second step – and this process would involve publicly consulting with interested parties.

"A reassessment provides the opportunity to carry out a thorough and robust look at the risks and benefits associated with neonicotinoid use in New Zealand."

New Zealand's decision aligned with the Australian Pesticides and Veterinary Medicines Authority's (APVMA) recent announcement that it planned to conduct a chemical review of neonicotinoid use in Australia.

"We plan to look for opportunities to work with our transtasman neighbours at the APVMA on some of the technical aspects of the environmental risks, given the broad similarities in products used in Australia and New Zealand," Holmes said.

The European Union has already voted to ban neonicotinoids – and groups here like the Soil and Health Association have been urging the Government to follow suit.


Yet the challenge for New Zealand was that the agents remained an effective way to control damaging seedling pests such as the Argentine stem weevil, black beetle, springtails, caterpillars and slugs.

They were considered less toxic to humans than organophosphate insecticides, and were considered a more environmentally friendly means of crop protection compared to broad-spectrum foliar sprays.

This was because they were highly targeted and therefore didn't have the same risks of environmental exposure and impact as aerially-sprayed agents would.

Further, they allowed crops and pastures to be established by direct drilling - where the seed was drilled into unploughed soil - thereby reducing nutrient leaching and carbon emissions.

University of Otago geneticist Professor Peter Dearden acknowledged neonicotinoids had obvious benefits over previous insecticides that have been used, both in environmental damage and human health.

"But evidence is gathering that they have had significant negative impact on beneficial insect populations and, more generally, on insect communities that underpin many of our ecosystems," Dearden said.

"In the past few years we have seen research showing the incredible damage we have done to insect populations, and are starting to reap the consequences of not taking as much care of them as we need.

"I hope this decision is part of the process of changing the way we deal with insects, recognising them as vital to our environment, ecosystem and health, rather than indiscriminately killing them."

The decision came after the EPA recently drew up a hit-list of 40 chemicals to reassess – although neonicotinoids, and similarly controversial chemicals glyphosate and methyl bromide, weren't among them.