"There are perhaps 800 to 900 businesses impacted by [the ban],and the number of consumers whoare being criminalised is by nomeans a marginal number."
Others in the industry have expressed similar anger at the surprise nature of the ban.
Chris Fowlie, the co-owner of the Hemp Store in central Auckland, said he would be left with $80,000 worth of stock to offload in two weeks.
Demand had already picked up since the ban was announced on Monday, and he had discounted the price of products, but he said he would still be left with a "mountain" of stock.
"We're going to have a big party and just smoke all of it. Because handing it in to police - that would just be a kick in the teeth."
Zaid Musa of Enjoi Products, one of the largest synthetic cannabis manufacturers in New Zealand, said he would be left with millions of dollars worth of stock.
Mr Musa said that when BZP-based party pills were banned, the industry was given six weeks before products could no longer be sold.
He has written to Associate Health Minister Peter Dunne and Labour leader Phil Goff requesting a changeover period of four weeks.
Mr Musa has instructed stockists to discount products, and said prices on orders made through his website had been reduced by up to 75 per cent.
He expected to have around 700kg of product left over, which would be shipped to overseas markets.
Legislation introduced in Parliament this week will allow Mr Dunne to class products as "temporary controlled drugs" and withdraw them from sale for 12 months.
During that time, a product will be assessed by a committee - appointed by Mr Dunne - which would judge whether it was safe to be sold.
Mr Dunne has said the bans are a stop-gap measure while the Government considers a Law Commission recommendation to require the industry to prove its products are safe.
Both Mr Musa and Mr Fowlie said that although products could be quickly banned, they could still be on the market for a significant amount of time before being detected and pulled.
"If the manufacturer labels it as plant food and fish feed, and only sells it in herbal high-type stores, you're not going to get any straight people going in there and complaining about it.
"Next Saturday there will just be new products out there. I don't think we'll have single day without them being on sale."
CLAMPDOWN
* Synthetic cannabis products will be banned from sale next Friday.
* They will be classed "temporary controlled drugs".
* All products will be assessed to decide whether they are safe for sale.
* Manufacturers are expected to be left with millions of dollars worth of stock.