The Green Party will hold a public hearing on animal testing of party pills and legal highs after a select committee refused to consider the issue.
The Psychoactive Substances Bill is due to be in force by August and an expert panel was last week named to set the safety testing regime for legal highs.
Producers and distributors of legal highs will have to have their products tested under the regime to prove they are low risk.
Associate Health Minister Peter Dunne said he was confident the panel would provide robust advice.
But animal welfare advocates are appalled that the testing regimes will include testing the products on animals.
The Anti-Vivisection Society wrote to Dunne in September recording their concern.
"While we applaud the intent and overall content of the proposal and support legislation that we believe meets the aims of ensuring the safety and wellbeing of New Zealand citizens, we hold serious reservations that the section that outlines the proposed use of animal models in the testing regime will help to do that," manager Stephen Manson said.
Toxicology testing on animals was unreliable and did not meet international best practice, he said.
He outlined a number of alternative testing methods.
In response, Dunne encouraged Manson to make a submission to the select committee considering the legislation.
But earlier this month committee chair Paul Hutchinson said animal testing was outside the scope of the committee's hearing.
"Possible amendments prohibiting testing these substances on animals are not related to the subject matter of the bill as introduced," he said.
Green Party MP and committee member Mojo Mathers said New Zealanders did not want party pills and legal highs tested on animals.
"The clear evidence is that we can test for the safety of these substances without the use of animals, and that such tests may even give more accurate results than animal tests do," she said.
Without specifically ruling out animal testing it was likely it would be contracted out, possibly to China where it was cheaper and the laboratory standards were "notorious".
"New Zealand needs this regulation to keep people safe, but New Zealanders don't want animals to suffer unnecessarily for recreational substances," she said.
Mathers will tomorrow hold a public hearing on the matter in the Green Party's parliamentary offices.
She intends to present a report on the hearing to her committee colleagues.
Dunne said animal welfare would be strongly represented with the appointment of the SPCA's Bob Kerridge to the expert advisory committee.
"This really does show that animal welfare issues will be to the fore in coming up with a testing regime to make sure legal highs are as safe as possible for young New Zealanders," he said.
Dunne said he made the recommendation that people submit to the select committee in good faith at the time but he understood the logic of the committee's decision not to hear from people on the issue.
A petition against animal testing will be presented to Parliament tomorrow and a rally is due to take place in Auckland.