The Environmental Protection Authority has declined an application to import or manufacture an insecticide for use in New Zealand because of the risk to bees.
The insecticide, Ortus, had been proposed as a seed treatment.
But the EPA had concerns that it would not adhere properly to seeds and that dust would be produced during sowing, posing a high risk to bees.
The insecticide contains an active ingredient, thiamethoxam, which is one of a group of chemicals known as neonicotinoids which the European Union has banned for two years while it investigates their effects.
The Green Party's agricultural spokesperson, Steffan Browning said he hoped the EPA's decision was an indication that it's taking a more serious look at those insecticides which are mainly used as seed coatings.
"Hopefully it will reassess neonicotinoids generally and follow the EU's position of severely restricting the use of three, effectively banning them on certain crops while they look at the effect on bees."
Steffan Browning said while one has been declined, there are other formulations still in use.
He said it's a good opportunity for the EPA to start a review of the other ones and hopefully restrict them.
New Zealand's agri-chemical industry said there's no evidence that Neonicotinoids are harming bees here.