Manufacturers of party pills could be prevented from testing their drugs on animals if they cannot prove it is worth the pain they could potentially cause.
Last year 37 per cent of the 327,000 animals used in research, testing and teaching in New Zealand died or were put down during projects.
Psychoactive drugs will join the group of products being tested on animals under proposed regulations for producers to prove they are safe before they go on sale.
Party pills are expected to be tested on dogs and rats, but the regulatory body for ethical animal treatment says strict criteria could restrict such tests.
Most of the 80,000 rodents and rabbits used in trials last year either died or were put down after the tests were complete.
"That kind of research is only going to be allowed if there is a proven benefit and if that benefit outweighs the cost to the animals," National Animal Ethics Advisory Committee chairwoman Virginia Williams said.
"Yes [it is a high standard to meet], and so it should be."
The 327,674 animals used in research, testing and teaching last year was a 35.3 per cent increase on the previous year, the NAEAC report says.
The most commonly used species were cattle, mice, sheep and chickens.
Most of the animals suffered little or no impact (85.5 per cent), although 5.4 per cent suffered high to very high impact, including 39 feral cats trapped, tagged and released to track how far the predators ranged.
Ms Williams said the NAEAC set strict regulations for the projects involving animals and all proposals were scrutinised to see where they could reduce the number of animals used, refine an experiment to minimise or eliminate any suffering and replace animals at any opportunity.
Ms Williams said all animals were ranked on a sentient scale. Those considered to feel less, such as fish, were preferred over those considered to feel more, such as dogs.
More than 1000 dogs were used in projects last year and 12 per cent either died or were put down. Associate Health Minister Peter Dunne said the amount of testing of party pills on animals was still to be decided but it was important because "human safety is the paramount consideration".
Mr Dunne said he had "a great deal of sympathy" for the view that it was sad to test legal highs on animals as opposed to testing necessary medicines.
"I understand that but I think we should see very different questions if we do not test these products and someone dies," he said.
SPCA president Bob Kerridge said there was no justification for party pills to be tested on animals.
Details of the proposed stricter regulations, which puts the onus on manufacturers to prove their party pills are safe, are expected to be released next year.
Animals that suffered "very high impact" included:
*Possums, rabbits, rats and stoats used in studies to identify more environmentally friendly and humane toxins and tools for pest control.
*Guinea pigs used for testing animal vaccines to demonstrate potency.
*1646 mice used for public health testing for food safety, mainly for algal bloom-induced marine biotoxins.
*A number of cattle died during on-farm animal husbandry trials, most of causes unrelated to the research projects they were involved in.
*39 feral cats were trapped, tagged and released to gain information on how far the predators range.
Source: NAEAC Annual Report