Skingraft owner David Young said customers were still unaware of the ban.
"We still get people coming in who haven't heard," he said.
"Then we've others saying it's [this] morning. When it's made public when the ban will happen there will be people buying in bulk.
"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.