Mr Dunne said the latest ban was "just another nail in the coffin of synthetic cannabis substances".
It comes after Customs intercepted a shipment of the chemical at the border in early November.
The chemical was tested by ESR scientists and was confirmed as the synthetic cannabis substance AM-2233.
This month the Ministry of Health was tipped off by two sources that the chemical was being sold in New Zealand in products, one of which was believed to be Tai High.
A ministry spokesman said products were tested only on suspicion or following complaints about individual products.
"There is a good level of awareness in the industry about the bans in place, and the ministry finds it is alerted promptly if products containing synthetic cannabis substances are made available for sale."
Tai High is believed to have been on sale only briefly, from early November this year.
Graeme Fletcher, the sales manager for smoking accessory retailer Pipe Dreams, said he was disappointed health officials had not alerted retailers directly about the ban.
The store did not stock Tai High but if it did, it could be prosecuted for failing to pull it from shelves.
"I would have thought they should have been more proactive. I mean, leaving it the other way round and going to the police - it's an ambulance at the bottom of the cliff," he said.
"If the law changes and we don't know about it because no one told us, you're trapped. Ignorance of the law is not a defence against the law."
The banned substances' list had changed the way Mr Fletcher sourced products from manufacturers.
"Unless they can authoritatively tell me that what they're giving me is legal, I don't want to take it. I don't want to sell it - I can't afford to make a mistake."
A Ministry of Health spokesman said the ministry notified manufacturers, and it was their responsibility to let retailers know.
It was unlikely a retailer would face court action if they did not know of the ban.
"The onus would be on them, but it's unlikely they'd be prosecuted. They're more likely to be warned."
Scott Mesarich, the owner of legal highs' store Wicked Habits, said he was surprised by the ban because Tai High was not as strong or as widely available at places like dairies as earlier synthetic drugs like Kronic.
"I thought if it was done more sensibly ... then these products might stay around a bit longer," he said.
"It just seems a shame that there's such a demand for this type of product and it can be sold in a regulated manner, and they just don't want to have any bar of it."
National Poisons Centre toxicologist Leo Schep said the centre has received one call, about a week ago, regarding the latest substance.
He had not had the chance to look at its structure, but it was believed to be similar to another banned cannabinoid.
Dr Schep said the Government's approach was working and the new law would make it even harder for manufacturers to find loopholes, because every time they tweaked a molecule they would have to prove it was safe.
"I'm confident that they're not going to get through that hoop, and it's going to be too expensive anyway. We're talking millions of dollars."
Tai High manufacturer Herbal Exports would not comment.
