Authorities must put the resources into regulating psychoactive substances, a leading drug expert says.
There must also be strict criteria for testing the safety of the substances, taking into account on how they will be used.
Submissions on regulations for the Psychoactive Substances Act close on March 21 and will provide the operational detail for how the new law will work.
The act requires manufacturers to prove, through testing, their drugs have a low risk of harm to the public before they can be approved for sale.
The act has had interim regulations in place since last July but once the consultation is complete the full regime comes into effect.
Massey University drug researcher Dr Chris Wilkins has published a research article in the international journal Addiction, which includes the regulations he believes should be in place.
He said there must be controls around how the drugs were tested before they hit the market.
"At the moment we don't know what tests they are going to use, but they have described them as similar to the tests they use for pharmaceuticals," he said.
"There is a fairly big difference from medicines, which you take obviously when you're sick, to recreational drugs, and the testing should reflect that."
Pharmaceutical-style testing would find the effects of using the substances to the recommended level but it would not reflect the way people used the substances, he said.
"That would include looking at what happens when you combine it with alcohol - clearly a lot of people are going to combine this product with alcohol," Wilkins said.
"The pre-testing has to reflect how people are going to use them outside the lab."
It would be hard for the testing to find the long-term effects of the drugs and the public should know that just because they had been deemed low risk, it did not mean they would be OK to use long-term, he said.
"They have been saying we're going to have clinical testing and the public often thinks that will determine for sure that these things are safe, but it is a much bigger challenge than that.
"You only have to think of tobacco.
"That was sold for decades upon decades before we established scientifically the link between smoking and lung cancer."
The other concern with the psychoactive substances was the monitoring of them once they were approved, he said.
"The industry has got to be taking responsibility in terms of monitoring what happens with their product and then there should be some sort of penalty if they don't obtain the standards we are looking for," Wilkins said.
"It's almost like getting the fox to look after the chickens because they are making incredible amounts of money every day, but then you are also asking them if something goes wrong with their product, let us know and we will take it off the market.
"So you can see the conflict."
Wilkins said there was also a concern at how easily the drugs could be counterfeited and the authorities would have to put the resources in to monitor that.
"We're already getting those reports from legal-high manufacturers now," he said.
"They are saying somebody is making this chemical and using our packaging when it's not even their products, it's counterfeit.
"A lot of these products are fairly easy to make and the chemicals are available in bulk from India and China.
"So there has got to be a commitment from the authorities to [provide the] resources to stop that from happening otherwise all we're going to do is have a semi-legal market and then a huge black market of counterfeit stuff that people can just pick up off the street."
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