The Environmental Risk Management Authority is looking at giving more weight to Maori spiritual values when it considers genetic research proposals.
The move goes against the concerns of many scientists, who say existing rules on Maori involvement are hampering research.
The authority is consulting on ways to better take into account Maori cultural and especially spiritual values in a revised policy, due to be issued in June.
It suggests, among other things, that Maori spiritual concerns about genetic research - even in the absence of any physical or biological risk - could be enough reason to reject research applications.
The suggestion is likely to alarm scientists, who say Erma's rules already hinder basic research.
Scientists applying for approval to conduct genetic research are encouraged to consult Maori - and must consult them if they intend to research native species - and their research proposals are evaluated on Maori values.
Canterbury University head of zoology Frank Sin, who abandoned his research into paua and lobster because Ngai Tahu did not approve it, warned that Erma must relax its rules or risk drive young scientists out of the country.
"I'm not losing anything by not doing this research but for the young academics this is their bread and butter.
"I can see for the younger generation of scientists it will be quite critical for them."
Professor Sin was blocked on two applications to Erma for permission to clone paua and lobster genes for subsequent research into how to improve their growth for commercial harvest.
He proposed putting their genes into bacteria to grow copies in a standard, lab-contained procedure that is also used to put human genes into bacteria to produce insulin for people with diabetes.
"We're not talking about developing new genetically modified organisms. We're just using a genetic technique in the lab. Yet I didn't get approval. So I just gave up."
Ngai Tahu spokesman Mark Solomon defended requirements for scientists to consult with Maori.
"It's so they can't fob us off," he said.
"We look at things in slightly different ways. Maori believe everything has a lifeforce that is a gift from the Creator and if you mix those lifeforces, what happens? That's not natural."
Ngai Tahu was the only iwi to be given "interested persons" status by the Royal Commission on Genetic Modification.
In its submission, it stated its "abhorrence" of those involved in genetic modification "acting as God and interfering with the blueprint of life".
Mr Solomon said the tribe did not have a blanket rule to disapprove all genetic research, and considered each application put before it.
He did not know if Ngai Tahu had ever approved genetic research.