Safe Food, a pro-organic group, is standing by a report on pesticide residues in vegetables and fruit, saying it reveals the effects of long term exposure to chemicals.
Safe Food analysed data supplied by the Ministry for Primary Industries, highlighting what it calls the 'dirty dozen' most contaminated foods.
They include imported grapes and other fruit, celery, bok choi, spring onions, cucumber and bread, which were all found to contain an organophosphate insecticide called chlorpyrifos.
The worst were grapes, with 35 different pesticides showing up in almost all of the samples tested.
But the Agcarm organisation, which represents agricultural chemical companies, has dismissed the analysis, with chief executive, Graeme Peters calling it alarmist.
In terms of quantity he said it would equate to less than one tenth of a teaspoon of residue in an Olympic sized swimming pool.
Mr Peters said anything is detectable these days, but that does not have an impact on the safety of the food.
He said crop protection products are regulated by both the Environmental Protection Authority and the Ministry for Primary Industries.
But Safe Food researcher Alison White, who is also a public health scientist, said the findings should not be taken lightly.
For example, she said exposure to the insecticide chlorpyrifos has been is linked to pre-natal damage in babies.
Ms White said if the foetus is exposed to even minute doses of this particular pesticide then it permanently alters the brain structure.