The organic food industry says a new treatment to be used in growing strawberries should have been rejected as too dangerous.
The Environmental Risk Management Authority has approved the use of the soil fumigant product Ripper, which contains methyl iodide.
It replace the use of methyl bromide which was prohibited five years ago because it strongly attacks the ozone layer. Methyl iodide is chemically similar but doesn't affect ozone.
The Soil and Health Association says the new chemical should have been turned down because it is 10 times more toxic to humans than the gas it replaces.
But the Strawberry Growers Association says the treatment will be used only under strict controls, and poses little danger to growers and none to consumers.
Horticulture chemical company Elliot Technologies has approval to import the product.
Technical manager Brian Smith says it is not harmful to the environment and will help growers sterilise soil when all other products fail.
He says controls are extreme compared to established products so it is likely to be a niche product with specialised use for difficult situations.
Mr Smith says the company hopes to have Ripper on the market by early spring.