The legal high industry says a blanket ban on the sale of the pills would cause more harm than tough regulations.
The sale of synthetic cannabis and some other legal highs was restricted under the Psychoactive Substances Act last year.
Hundreds of people calling for a complete ban on the sale of legal highs protested in more than 20 locations from Whangarei to Invercargill at the weekend.
A protest organiser says the next step is to take the battle to ban legal highs to Parliament. Julie King from Tokoroa, says the protests had great support both from those taking part and from passers-by. She says they'll now focus on an official petition.
Napier mayor Bill Dalton is also among those calling for an outright ban
But Star Trust director Grant Hall says evidence and expert advice given to the Government shows strict regulations will provide better public health outcomes.
Mr Hall says a blanket ban would hand the sale over to organised criminals, who do not check ID, worry about quality control, or pay taxes.
"What we know from the evidence and the expert advice and all the scientists that advise the Government is this, that if we strictly regulate this product we will get better public health outcomes. This is a marketplace that doesn't disappear by banning it. It's never worked ever."
Labour's associate health spokesperson, Iain Lees-Galloway, says the Health Ministry doesn't have the resources to properly manage the Act and they are not able to deal with complaints in a timely manner.
But Associate Health Minister Peter Dunne says he's happy with the level of resourcing.