A Ministry of Health report has backed the decision to allow the release of imported dung beetles onto New Zealand farmland.
The Environmental Protection Authority's predecessor ERMA approved the import of 11 exotic species of dung beetles two years ago.
The aim is to use them to help break down and spread the animal droppings that cover an estimated 700,000 hectares of pastoral farmland in New Zealand, in the process improving soil health and productivity and reducing nutrient run-off from pasture.
The Ministry of Health commissioned a report after some scientists and health officials raised concerns about the beetles' potential to spread diseases affecting humans and animals, such as E. coli and salmonella.
EPA new organisms applications manager Asela Atapattu says it supports the original decision to allow the beetles into the country.
He says the latest report has confirmed the original risk assessment that there are no human health risks from dung beetles and that the original decision was sound.
The group running the dung beetle project released the first of them on an organic dairy farm in Southland on Thursday, and is planning further releases in other parts of the country.
Southland Regional Council biosecurity manager Richard Bowman says if the beetles perform as expected, they will be providing farmers with a free soil improvement and environmental service.
He says it is hoped it will break up the dung on the surface more quickly, that nutrients will be spread around, that the soil will be more open and aerated so water can move through it more effectively and that nutrients can be absorbed more readily into the soil.