Those working in the 'legal highs' industry believe banning certain products will only lead to the creation of new ones.
Urgent legislation going before Parliament today will allow all 43 current synthetic cannabis products to be classed as "temporary controlled drugs" and withdrawn from sale.
Associate Health Minister Peter Dunne will have the power to place products in the category, which would ban them for 12 months.
During that time, a product would be assessed by a committee - appointed by Mr Dunne - which would judge whether it was safe to be sold.
Yesterday the Prime Minister John Key suggested that the government could go further.
He said the long term aim was to introduce legislation which required makers to prove the drug was safe before it could be sold.
He said other substances such as party pills would be considered as part of longer term changes, but the immediate concern was about the 43 drugs which will be targeted in today's legislation.
However those working in the industry say the move is dangerous, and will have the effect of sending users to the black market where there are no controls.
Hempstore manager Chris Fowlie told Newstalk ZB he believed the ban encourages the creation of new products, but only one at a time.
"When that one is banned they'll introduce the next one," he said.
"Rather than, for example, having several varieties of synthetic cannabis, you might just have one that's out there and sell as much of that as you can until it's banned and then put out the next one."
Mr Fowlie says the industry's frustrated as they've already spent lots of money on labelling and marketing, believing they were heading towards R18 regulation, rather than prohibition.
Meanwhile an Auckland business advocate is praising local business for its part in having synthetic cannabis banned.
The ban comes a week after the Auckland Chamber of Commerce wrote an open letter to all MPs.
Chief executive Michael Barnett told Newstalk ZB in just 48 hours, he gathered a thousand responses - not one in favour of the products.
"Employers in the Auckland region should be pleased that in some way they've contributed to getting these products off the shelf," he told Newstalk ZB.
"They can't come off quick enough, we need to stop using our children, the public as guinea pigs."
The Herald understands people will not face charges if found with a small amount of a banned synthetic cannabis - which the industry says will lead to stock-piling.
Massey University senior researcher Chris Wilkins said the banning of BZP-based party pills showed what the effect of banning synthetic cannabis would be.
Forty-nine per cent of men aged 20 to 24 had used BZP-based pills in 2006 but since their ban, use of legal substitutes had been minimal.
- with Newstalk ZB and NZ Herald staff