Horticulture New Zealand has called for more testing of fruit and vegetable imports to ensure suppliers are complying with the conditions for sending produce here.
Biosecurity New Zealand has suspended imports of Australian tomatoes after residue testing by an independent advocacy group showed the fruit had not been treated with the pesticide dimethoate, which is used to kill fruit fly.
New Zealand tomatoes were recently allowed back into Australia, with tighter controls, after being suspended because of a bacterium found in Auckland greenhouses.
Horticulture NZ chief executive Peter Silcock says all produce imported into New Zealand undergoes rigorous checks and it is disappointing that Australian growers appear not to be following the import rules. He says fruit fly is one of the biggest threats to New Zealand's horticulture industry.
The Soil & Health Association says it was actually testing for another pesticide, endosulfan, and it was only by chance that it tested for dimethoate as well.
Biosecurity New Zealand is asking Australian authorities for evidence that the pesticide is being applied, and the correct procedures are being followed.
The agency says it is not sure how long the suspension will remain in place, but it hopes to have the matter resolved in the new year.