Today is the last day people can legally buy synthetic cannabis but users will not be able to stock up - once new laws pass it will be an offence to have it in your possession.
Parliament was in urgency last night to amend the Psychoactive Substances Act.
Rotorua policeprevention manager Inspector Ed Van Den Broek said the ban would mean it would be against the law to sell or be in possession of unapproved psychoactive substances.
He said Section 71 of the act ruled a person committed an offence if the person had a psychoactive substance that was not an approved product in his or her possession - when the ban comes into effect there will be no approved products.
Retailers were unsure what reaction to expect, with lots of speculation in the past week as to when the blanket ban would come into force.
"The police came in and we talked about it. But what's to stop someone from going outside then coming back in again."
Special T Discounters yesterday hired a security guard in case of any rush buying at the Tutanekai St store last night.
Staff have been advised not to talk to media and the owner did not respond to our request.
Adult World owner Kevin Stephens said his Eruera Rd shop had "a few regulars" but they weren't expecting a last-minute rush to stock up.
"There's no indication that stockpiling is going to happen," he said.
Wild Things owner Sue Rutherford did not return our call.
Mr Van Den Broek said the CBD community constable and other police staff would carry out spot checks at the four shops to ensure the products were no longer being sold.
"Police expect to see full compliance by these retailers," he said.
