The Greens aren't about to soften their opposition to genetic modification, after more than 100 Nobel laureates have said it's based on emotion and dogma.

In an open letter, they've said there's no risk to human health, and opposition to genetically modified food should be dropped. Their view has academic support in New Zealand.

But Green co-leader James Shaw said that's not going to change anything here.

"There is a huge market out there for people who want safe, GE-free organic food, and it's very, very hard for us to do that when you introduce that into New Zealand."

Mr Shaw said this country should be proud it's food is free of genetic modification.

"New Zealand has access to those markets that are willing to pay a really high price for high quality organic produce.

"A tonne of organic milk powder goes for about $14,000 - you compare that to regular milk powder, it's going for about $2300 a tonne."