Prime Minister John Key has ruled out any animal testing on legal high products.
Parliament will pass legislation this week to pull all legal high products from shop shelves until they can be proved to be safe.
Mr Key had previously ruled out recreational drug testing on all animals except rats, he told Newstalk ZB.
"The advice I've had from the Health Department over the weekend, and having had discussions with Peter Dunne, is that they don't believe that that's safe.
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"They say it has to be on two species, not one, so what I've said is, 'Okay, well if that's what you believe, then it's all out'."
Mr Key said if the product could not be tested other than with animals, then it failed to meet the testing regime and would not be produced.
The decision is likely to be broadly welcomed, after a Labour Party petition calling for a ban to animal testing of legal highs was signed by 40,000 people.
Mr Key told TVNZ's Breakfast show the Health Department had told him and Mr Dunne that to ensure a product was safe, it needed to be tested on rats and rabbits.
"It's one thing to test on an animal if you're developing a life-saving drug for cancer - it's quite a different issue for a recreational drug."