The New Zealand Racing Board and New Zealand Equine Health Association want to import Proteqflu and Proteqflu Te vaccines, both of which contain genetically modified canarypox virus.
The Te version is the same but contains an additional non-GM component for protection against tetanus.
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 in an outbreak which began in August last year.
The vaccine would also be used for horses being exported to countries where its use is an import requirement.
The Environmental Risk Management Authority (ERMA) has released its assessment report, which concludes 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 tomorrow's hearing.
The application, if approved, would be the first conditional release of a genetically modified organism in New Zealand.
ERMA's responsibility is limited to the GM micro-organism component of the vaccine. Approval to use the vaccine must also be obtained from the New Zealand Food Safety Authority's Agricultural Compounds and Veterinary Medicines group.
The New Zealand Green Party has voiced its opposition to the vaccine, arguing it would endanger the country's GM-free status.
The hearing is to start at 9am at the Terrace Conference Centre, St John's House, 114 The Terrace, Wellington.