Environment Minister Nick Smith says more genetically modified organisms may get approval for use in New Zealand and he has dismissed as impractical local councils' opposition to them.
The Environmental Protection Agency this week approved the importation of the Pexa-Vec virus, which is used to combat liver cancer. It is the first GMO to get New Zealand approval as a human medicine.
Dr Smith told The Nation today the scientific advice was that there was little chance the virus would spread or survive outside a tumorous liver.
About 180 New Zealanders died from liver cancer each year, he said.
"We do not want to deny people access to life-saving treatments on the basis of knee-jerk political reactions, slogans like 'GM-free'."
Dr Smith admitted he was leaving the door open for the threshold for approval of GM changing.
There was an international argument about what was a GMO and what was not.
"When you're bringing in foreign DNA into an organism there's no question in my view that that's a genetically modified organism.
"Where it gets more tricky is when there are alterations to the genes of an organism within it."
Humans had been selectively breeding, using techniques to enhance mutations for decades, he said.
"When you use those older techniques of enhancements of the mutations that occur naturally within an organism, at what point, where is that line?"
There was a wide range of definitions of the line but New Zealand needed to be cautious, he said.
"New Zealand does have an important brain for natural products, we earn a lot of our living from food products, but also we are a country that has got a pretty proud heritage of leading in science."
Earlier this year, Hastings District Council declared itself a GMO-free food-producing region, but Dr Smith said it was "impractical and wrong for councils to try and regulate this separately".
"It is impractical to have 86 different councils rules around GM. If you get in a car and you drive from Hastings to Gisborne or to Wairarapa, if you had trees that are GM, there is no biological barrier for those to spread."
Councils were welcome to submit to the EPA, and he had confidence in its robust and thorough processes.