The head of the National Animal Welfare Advisory Committee says testing party pills on animals may not get through a strict ethics process.
The Government wants the same standard of testing for legal highs as for new pharmaceuticals to ensure they are safe, which means some form of animal testing.
Associate Health Minister Peter Dunne has ruled out a test in which doses of a drug are given to a sample group of animals until half the test group dies.
But he says other forms of animal testing are still possible as he looks to introduce legislation changing how New Zealand regulates party pills and other legal recreational drugs.
National Animal Welfare Advisory Committee chairperson John Hellstrom told Radio New Zealand's Nine to Noon programme New Zealand has a very strict animal testing regime.
He says any proposal must first go before the committee which analyses whether the welfare cost is justified by the benefit that would come from the use of the product.
"When you get to something like a recreational drug, how you define the benefits becomes a little intriguing."
Dr Hellstrom says animal testing will show whether a drug is poisonous or causes cancer but it won't establish whether it causes psychotic episodes in humans.
Animal welfare group Paw Justice says it's likely the other forms of animal testing being considered will still result in animal harm and deaths.
And spokesperson for the group SAFE, Hans Kriek, says international research shows drug testing can be done without using animals.
Mr Dunne says no decisions have yet been made as officials look at all alternatives to animal testing. "I won't rule things in or out until we have all that information and can make a balanced and proper final decision."