"We are sacrificing animals at the altar of recreational drug use," he said in an emotional speech to Parliament.
Associate Health Minister and Rotorua MP Todd McClay disagrees and says "a degree" of animal testing is necessary to guarantee party pills and synthetic cannabis are "low-risk". But even though it is the first time animals will be lending their bodies to research on recreational drugs, vivisection in New Zealand is well established.
According to the Ministry of Primary Industry's most recent figures, 327,674 animals were used in research, testing and teaching in 2011.
An average of 300,000 animals are used for testing each year, and experiments are carried out in universities, schools, polytechnics, commercial laboratories, government departments and ministries.
The most commonly used species for testing is cattle, followed by mice, sheep and chickens.
Most cattle survive the testing, but mice are not so lucky, suffering a 97 per cent mortality rate.
Animal testing is strictly controlled under the 1999 Animal Welfare Act and regulated by the National Animal Ethics Advisory Committee, which comes under the ministry.
Mandy Carter, campaign manager for animal advocacy organisation Safe, says test animals are subjected to surgery without anaesthetic, food deprivation and extreme temperatures.
The ones that survive the tests are usually killed so their bodies can be examined for further effects.
In one particularly invasive experiment, cattle have a hole cut in their stomachs and are fitted with a "little window" with a flap so scientists can reach inside for samples at any time of the day, she says.
Tests can be short-term or long-term and animals often come from breeding laboratories.
In 2011, a beagle breeding and research facility was shut down in the Manawatu and the terrible conditions exposed on TV3's Campbell Live.
The beagles at the Valley Animal Research Centre, like many other animals used for testing, were being raised solely for medical research.
They were then being sold to unsuspecting buyers on Trade Me, who found their new pets were suffering from a range of health issues.
Most had behavioural problems and some died.
Products now on the New Zealand market that have been tested on animals overseas include Estee Lauder cosmetics, L'Oreal, Avon and Revlon.
A locally made anti-ageing skin cream called MitoQ recently caused a stir after it was revealed to have been tested on animals in New Zealand.
To test on animals in this country, companies have to prove that the benefits of a product outweigh the animal's suffering, Miss Carter says.
But Safe wants cosmetics testing banned across the board and will be handing a petition to the Government this month.
Quoting a New Scientist article from December last year, Miss Carter says 92 per cent of new drugs fail clinical trials, even though they have passed animal tests successfully.
For example, six people enrolled in a UK trial of the cancer and arthritis drug TGN1412 in 2006 were hospitalised after developing multiple organ failure, despite the drug having passed animal tests successfully, the magazine reported.
Miss Carter doesn't know of any medical products on the market here that animals have helped prove safe for humans, and recreational drug testing was another step in the wrong direction.
"This is purely so that people can go out and have a bit of fun at the weekend. There's nothing remotely essential about it," she says.
Toxicity testing for party pills would be done on dogs and rats, and would involve force-feeding with a syringe or tube, she says.
The ethics committee's chairwoman, Virginia Williams, says animal testing is necessary, well-regulated, and done to ensure the safety and quality of products for both humans and animals.
Any organisation or company wanting to use animals for testing has to hold a code of ethical conduct approved by the director general, Ministry of Primary Industries, she says.
The code must also be approved by an animal ethics committee with at least four members who are not affiliated with the company and have been nominated by the New Zealand Veterinary Association, the RNZSPCA, a territorial authority or regional council.
By the numbers
According to 2011 data, 327,674 animals were used in research, testing and teaching - a 35.3 per cent increase from 2010.
85.4 per cent of those animals were exposed to "manipulations", which had no, or little impact on the animals' welfare.
A total of 17,581 animals experienced vivisections of "high impact" or "very high impact" - 5.4 per cent of the total.
More than 63 per cent of the animals returned to their normal environment after testing.
The most commonly used species were cattle, mice, sheep and chickens.
The species that experienced a "very high" impact were rodents, fish, pest species and a small number of farm animals.
More than 97 per cent of rabbits and rodents die, or are euthanised following vivisection.
