The Government will have to look at New Zealand's genetic modification laws in the wake of a major report on emissions, Climate Change Minister James Shaw says.
But his Green Party isn't budging on its long-standing opposition to GM.
The Government's Interim Climate Change Committee this week raised prohibitive New Zealand regulations around genetics as a potential obstruction to lowering emissions on farms.
"New Zealand's rules on genetic modification could be a barrier to developing lower emissions technologies," the report said.
It gave the example of a genetically modified ryegrass developed by AgResearch that may potentially reduce both methane and nitrous oxide emissions from grazing animals, but that is having to be tested in the United States and would not be able to be used in New Zealand under current laws.
"The science surrounding genetic modification has evolved," the committee said.
"Other countries have changed their rules in recent years and it is not uncommon for livestock overseas to eat genetically modified feeds."
Greens co-leader Shaw said Cabinet had accepted it had a responsibility to at least look at questions that had been raised about regulation, including around genetics.
"If we are going make progress on this, if they are challenging us and saying that they think the regulatory environment we have essentially fails us in terms of producing the climate outcomes that we need, then we need to take a look at them," Shaw told NBR.
But he said there had been no decisions made and the Government would have to be "incredibly careful" about changes.
"The consumer brand that we have internationally for the provenance of our food, around 100 per cent pure, is incredibly hard-won.
"Anything you do that could endanger that could be well not be worth any of the benefits, even if this thing is scientifically safe ... The level of public anxiety around things like gene editing and genetically modified organisms is really high."
That concern was also raised in the commission's report.
A Government review could spark heated debate within the Green Party, part of whose membership is staunchly against loosening rules around genetic technologies.
Its official policy calls for the prohibition of "genetically modified and transgenic organisms that are intended for release into the environment or food chain".
A spokeswoman for the party said the policy remained unchanged.
Conservation Minister Eugenie Sage has stopped genetic engineering work being conducted as part of the Government's predator-free programme, saying she didn't want go down the GE "rabbit hole".
National Party climate-change spokesman Todd Muller on Thursday said Shaw was still being overly cautious and a debate was needed.
"We need to be honest with New Zealand and say: 'Look, cows and sheep are a challenge from an agricultural emissions perspective. There's technologies that are around that can mitigate that. Let's reflect on what that could look like," he said.
"We can't say this is a problem but we aren't willing to apply all science to the solution."
Federated Farmers vice-president Andrew Hoggard, meanwhile, said the industry wanted to have the option of genetic modification put on the table.
"The rest of the world is going in this direction," he said.
Environment Minister David Parker earlier this year confirmed no changes to legislation were being looked at.
The Government's previous chief science adviser, Sir Peter Gluckman, warned the legal framework was out of date in 2018 and the Royal Society has been looking at the issue.