''Without the use of Hi-Cane, the amount of flowers and fruit produced in many of the country's growing districts would become uneconomic, especially in warm winters.''
The product's risks could be managed through existing controls and industry best practice, Johnson said.
The industry has previously said no effective replacement for Hi-Cane is currently available, though research is continuing into some promising alternatives.
That is disputed by Levers, who maintains alternatives are already on the market.
The current Northland Regional Council rules for using agrichemicals such as Hi-Cane include carrying out a risk assessment and using a nozzle designed to reduce drift if spraying within 100m of "sensitive areas" such as homes, waterways or public roads, and no spraying within 100m if the wind is blowing towards a sensitive area.
The 2005 industry guidelines — which the NZKGI says have been superseded by the NRC rules — included a 10m setback from the property boundary for orchards bordering sensitive areas, or 30m if there was no shelterbelt or screen to catch spray drift.
Hi-Cane is used in the absence of frost in warm areas such as Northland to ensure uniform bud-break, so the vines produce plenty of fruit which ripens around the same time. It is generally used in August.
The EPA confirmed on Friday it believed there were grounds for re-assessing products containing hydrogen cyanamide because significant new information relating to its effects had become available.
Six products registered under the Agricultural Compounds and Veterinary Medicines Act contained hydrogen cyanamide as an active ingredient, including Hi-Cane.
However, establishing grounds for reassessment is only the start of a two-step decision-making process.
The EPA will next consider factors such as manufacturing and import volumes, exposure mitigation measures and the existence of alternatives beofre deciding whether to go ahead with a re-assessment.
Levers started his campaign in August and said he had been working on it almost full-time since then.
News of a possible clampdown on Hi-Cane comes amid a boom in kiwifruit planting around Kerikeri.
Craigmore Sustainables is planting a 137ha former dairy farm along Wiroa Rd, near Bay of Islands Airport, in mostly gold kiwifruit.