Nearly 30 kiwifruit growers have escaped with a warning after admitting to misusing a heavily regulated chemical on their produce.
It follows an investigation by the Ministry of Primary Industries (MPI) into the misuse of the antibiotic streptomycin.
It found 45 different orchards, under the management of 26 growers, had misused the chemical, which is widely used to combat the vine-killing disease PSA.
Many growers admitted to injecting their kiwifruit vines with the antibiotic.
The practice constitutes a breach of the Agricultural Compounds and Veterinary Medicines (ACVM) Act 1997, which holds maximum penalties of a two year jail term or $15,000 fine for an individual, or a $75,000 fine for a corporation.
The investigation was launched after ONE News discovered in May that desperate kiwifruit growers had been illegally injecting their vines with streptomycin, in an attempt to combat PSA which was ravaging kiwifruit crops across the country.
MPI director of compliance, Dean Baigent, said the main aim of the investigation was to identify every case of misuse in order to isolate all affected fruit and prevent it from being sold.
"In this we were successful, and both domestic and international markets were able to be assured that no fruit with streptomycin residues was in the supply chain," he said.
Throughout the investigation MPI worked closely with the kiwifruit marketing body Zespri, which co-ordinated a declaration process for growers to come forward if they felt they had breached the conditions.
"There was a 100% response from growers, and those concerned have co-operated fully throughout the investigation," he said.
Baigent said a formal warning letter was an appropriate conclusion to the investigation.
"Throughout this process, MPI has been mindful that the country's kiwifruit growers are facing a desperate situation with PSA threatening their livelihoods," he said.
"The growers concerned voluntarily disclosed their wrong-doing, and those who misused product on a larger scale sustained the largest losses through the disposal of their affected crop.
"Additionally, the growers concerned have all been informed that any future breaches of the ACVM Act will result in prosecution."
Streptomycin has been used as a pesticide spray in New Zealand since the 1960s.
It was approved by MPI for use on kiwifruit under strict conditions to avoid any possibility of chemical residues remaining in the fruit.
The controls include a maximum of three spray treatments onto leaves prior to vine flowering.
It is currently the most powerful tool known to prevent PSA infection.