Police are asking retailers in Otago to stop selling legal synthetic cannabis as its effects are putting a strain on the health system.
Sergeant Chris McLellan says police visited stores selling K2, which is restricted to those over 18, and encouraged them to remove the drug from shelves due to the flow-on effects users are having on the health system.
He says the product, which can make users aggressive, anxious and hallucinate, is also a "driver of crime", he told the Otago Daily Times.
"People on the substance are doing things that they would not normally do at other times," he said.
Last month the Southern District Health Board (SDHB) reported a rise in the number of assaults on mental health workers which they blamed partly on the rise in the use of synthetic cannabis.
Synthetic cannabis use was more prevalent than alcohol or illicit drug use among some mental health patients and a new temporary law banning the substance is not working, a SDHB spokeswoman said at the time.
Sgt McLellan says K2 had appeared for sale in K2-only "tinny houses", two of which had been found in Balclutha and Dunedin.
He says retailers had given a mixed reaction about removing the product. Some said they would continue selling it until it was declared illegal.
K2 is being tested by health officials who will determine whether it will join 28 substances placed under temporary class drug notices. So far 50 synthetic cannabis products have been made illegal since last year.
New legislation will be introduced later this year requiring manufacturers to provide toxicology data and results of human clinical trials to a new regulatory body, which will declare whether they are safe before they can be sold.