A group wanting to release imported dung beetles on to New Zealand farms still hopes to do so later this year, despite concerns about the risks of disease.
Five species of dung beetle brought in from Australia are being bred in containment and assessed in caged trials before their planned release.
The Dung Beetle Release Strategy Group said the beetles will help break down manure on pasture, fertilising the soil and reducing emissions and run-off but some scientists and health officials have raised concerns about their potential to spread diseases affecting humans and animals, such as E. coli and salmonella.
Auckland University Dean of Science Dr Grant Guilford has questioned whether those risks had been properly assessed by the former Environmental Risk Management Authority which allowed the beetles in to New Zealand.
The Environmental Protection Authority, which replaced ERMA, is standing by the decision to release the beetles, saying it is supported by rigorous science.
AgriLINK NZ project manager Andrew Barber said that having the debate surface at this stage of the three-year project has been frustrating, but the group is confident it will be able to continue with the programme.
He said the EPA is emphatic that it has been thorough in its processes. It has reviewed all the research and reviewed it again when questions were raised.
Mr Barber said he's convinced allowing the release of the beetles is the right decision and points out that Australia took the step 40 years ago.
"The question might be more about why we have taken so long to pick up on this," he said.