The Environmental Risk Management Authority has approved an application to conditionally release two vaccines for equine influenza, subject to strict conditions.
The ProteqFlu vaccines contain genetically modified canary pox virus.
Dr Kieran Elborough, who chairs the authority's decision-making committee, said the vaccines would only be able to be used if there was an outbreak of equine influenza in New Zealand or to meet the biosecurity requirements of other countries for horse imports.
"The committee considered a range of international scientific evidence and considered 29 submissions from the public," she said.
"In reaching its decision, the committee evaluated the possible effects on the natural environment, the economy, people and society and Maori values."
The committee considered all potential risks from the use of vaccines ProteqFlu and ProteqFlu Te and concluded that potential benefits of the application outweighed the risks. The two vaccines have the same GM component, but the latter provides additional protection against tetanus.
The vaccines have been approved by the European Medicines Agency since 2003 and no environmental risk has been identified with their use.
The application to import for release the vaccines was submitted by the New Zealand Racing Board and the New Zealand Equine Health Association.
Based on the biological characteristics of the organism and controls imposed on how it is managed, the committee said it was highly improbable that it would adversely affect the New Zealand environment. The virus does not replicate or survive in mammalian cells.
The controls placed on the use of the vaccine include that it can only be administered by a trained veterinarian.
Records of the vaccine use must be maintained and made available to the Ministry of Agriculture and Forestry Biosecurity New Zealand. The vaccines must be stored in a secure location and expired vaccines must be disposed of as hazardous waste.
ERMA New Zealand's approval relates solely to the genetically modified component of the vaccines. Use of the vaccines will also require the approval of the Agricultural Compounds and Veterinary Medicines group of the Food Safety Authority.