The 135-page assessment and review was carried out by Erma after an application by the New Zealand Racing Board and New Zealand Equine Health Association to import Proteqflu and Proteqflu Te vaccines, both of which contain genetically modified canarypox virus.
The groups want approvals in place in case New Zealand suffers an outbreak of the highly contagious disease. The vaccine was a key tool in Australia's eradication of the flu.
Erma's assessment concluded that the proposed conditional release would pose a negligible risk to the environment, human health and safety, and the economy.
Erma's report will form part of the information to be considered at a public hearing on the application in Wellington on October 7.
The agency noted that the application, if approved, would be the first conditional release of a genetically modified organism in New Zealand.
Erma said in its assessment that it had identified the following pathways with potential risks:
"Studies have also demonstrated that the vaccine virus cannot replicate in mammalian cells or cause canarypox disease.
"Based on the biological characteristics of these two GM viruses and in addition to the proposed controls regarding the administration of this vaccine by a veterinarian, the agency considers it highly improbable that the organisms contained in the vaccines could form a self-sustaining population.
"The agency recommends that if this application is approved, then the approval should also cover any updated GM vaccines approved by the European Medicines Agency (EMEA) and/or United States Department of Agriculture (USDA) to vaccinate against new circulating equine influenza strains that have arisen due to mutations in the equine influenza haemagglutinin gene."
Erma said some submitters thought the application did not have sufficient information, and that there was a lack of independent data verification. No independent data for Proteqflu and Proteqflu Te was identified.
Two submitters also expressed concern about the first commercial release of a genetically modified organism:
"As the first commercial release of a GM organism [in] this country this application requires a comprehensive evaluation," said one.
"As a first conditional release the distribution of benefits and risks are of concern to the whole of the New Zealand public who share in our overall national identity, values and wellbeing," said another.
Several raised concerns that horses may excrete or shed the vaccine or GM viral particles, while others expressed concerns that we would be polluting or contaminating the environment by using GM vaccines.
Erma said environmental testing of the West Nile Canarypox GM vaccine showed that the virus was not detected in horse faeces, fresh grass, dry grass or horse urine after 30 minutes.
"Studies have demonstrated that these live GM vaccines are safe to use and do not persist or spread when tested in a variety of species including horses, canaries, ducks, chickens and guinea pigs."
Several submitters raised concerns that the conditional release of the GM vaccine virus could result in unanticipated effects on the environment.
"This vaccine has been registered for use internationally including in the European Union since 2003 and no unanticipated effects of the GM vaccine on the environment have been reported," the assessment said.
Erma said a significant concern expressed by GE Free NZ and others was that approval of the vaccines could lead to more GM approvals and loss of the New Zealand's GE-free status.
"This was expressed also in terms of concern about New Zealand's clean green image.
"The agency recognises the importance of perceptions, but considers that such a restricted activity would not result in potentially significant adverse effects on perceptions of New Zealand or the New Zealand environment."
The Ministry of Agriculture and Fisheries made comments in respect of parts of the application, but said it did not support or oppose the application.
The Conservation Department said, as a government department, it must remain neutral on the issue of genetic modification and the merits or otherwise of New Zealandís GM-free status.
"As such, this application has been viewed solely on the basis of assessing the risk of these vaccines to our native environment.
"The Department considers that these vaccines would be very useful additions to those vaccines already registered for use here. They appear to be the superior vaccine available against EI, and we consider it is important to have the best available defence against this disease."
It traversed several controls it said should be enforced "to maintain the safety of these products".