The green light has been given for a genetically modified organism to be brought into the country for a clinical trial for a new liver cancer treatment.
The Environmental Protection Agency has approved an application to import and use a genetically modified live vaccinia virus, Pexa-Vec, in the phase three trial involving New Zealand patients.
Pexa-Vec is a weakened virus, based on a vaccine used in the eradication of smallpox.
The modified virus is injected directly into the cancer tumour, to grow inside these rapidly growing cancer cells and kill them.
More than 300 overseas patients with advanced cancers have received Pexa-Vec treatments in previous clinical trials, the EPA says.
The decision to grant approval followed a thorough assessment by the EPA of the potential risks to the health and safety of the public, any valued species, natural habitats or the environment.
The EPA said a number of controls have been put in place to manage the risks to people and the environment, including restrictions on who can receive the virus, how it is administered, education of trial participants, provision and collection of biohazard containers for waste, and reporting and notification requirements.
Approval is still needed from Medsafe for the clinical trial to proceed.
Environment Minister Nick Smith is backing the EPA's decision.
"New Zealand has very cautious laws in respect of genetically modified organisms but we need to be open to biotechnologies that offer real benefits," he said.
"Liver cancer is a deadly disease and we need to support the development of innovative medical technologies that have the potential to save hundreds of lives."
Pexa-Vec is the first genetically modified organism to get approval as a human medicine under the Hazardous Substances and New Organisms Act 1996.