Federated Farmers is investigating suspected biosecurity breaches in imported palm kernel.
The product is being imported in containers and bulk shipments from Indonesia as a feed for dairy herds.
Biosecurity NZ has found 106 live insect species at eight bulk storage sites holding palm kernel: 99 of these were species already present in New Zealand and are considered likely to have infected the shipment after it arrived.
However, many grain farmers fear the remaining seven species are still being allowed to enter the country by Biosecurity NZ's monitoring regime.
Federated Farmers is asking members to keep an eye out and report any sightings.