Officials debating a new "legal high" testing regime sought clarification over how cannabinoids - fake cannabis products - could be tested on animals.

Ministry of Health documents sourced under the Official Information Act show the working party stated that products would have to be ingested by animals in the same way that they would be by future human consumers.

One of the discussion papers sought the opinion on how combustible "legal highs" could be tested on a animals.

The advice provided states: "There are some standardised methods to administer combustible products to animals. . . One method that has been modified by various researchers involves smoke from a cigarette; for example, being drawn through tubing to a manifold at precious flow rates using a vacuum pump and flow regulator.

"Animals are placed into holding tubes that fit snugly into the manifold, consisting of ports for nose-only exposure. Investigators also used a solenoid-puffing device to alternate the flow of smoke and fresh air to the animals."

The document said an animal could be administered a "defined number of cigarettes staggered over each day for a defined period of time" by this method.

The Sunday Star-Times revealed earlier this month that Ministry of Health officials had recommended a regime which would see designer drugs being tested on dogs and rodents.

The proposed tests include the lethal dose 50 per cent (LD50) test, where doses of the drug increase until half the test group dies. The method is banned in Britain and is not recognised by the OECD.

The idea has been met with widespread condemnation, with Green Party animal welfare spokeswoman Mojo Mathers labelling it "barbaric".

The Star-Times' December 2 report saw Associate Health Minister Peter Dunne back down on his stance about animal testing.

Animals would ingest the intended "legal highs" in the same way future human consumers would - in pill form.

Initially he said the tests were an "unpleasant but necessary reality".

But after the story was published, Dunne ruled out the use of LD50 and said no decision to use other testing methods involving animals would be made without a thorough consultation period.

But the proposed regime does have its backers, including National Poisons Centre-based toxicologist Leo Schep.

As well as being a vocal supporter, he confirmed to the Star-Times on Wednesday that he was part of the working group which proposed the regime.

"I have been one of a number of people that the ministry has taken advice from," Schep said.

"I contributed to that process... as did other people."

When asked if animal testing was his idea, Schep stated: "That was one that was debated for a while... If you are going to go down that line, you can't test [these compounds] on humans. You have to test on animals."

He last had discussions with the ministry six months ago on the proposed testing regimen, adding that the subject of animal testing had been "well-thrashed out" in discussions.

Meanwhile, party pill industry advocate Matt Bowden - who describes himself as the "Godfather of Legal Highs" on his LinkedIn profile - was reluctant to comment on the animal testing debate, saying: "Let's just see how the story pans out.

"After the [Sunday Star-Times] story... the Greens put some stuff out on horrific images [of animal testing] and there is a lot of negativity about it. I'm just a little bit over it to tell you the truth. I don't really want to talk about it."

- © Fairfax NZ News