The availability of New Zealand-made mock cannabis cigarettes in Australia has prompted a workplace safety warning there.
The Australian mining industry is telling workers who use the legal products such as Spice, Kronic and Dream to think about the safety of their colleagues.
The cigarettes contain vegetable matter that is sprayed with a chemical, naptholindole, which produces similiar psychoactive effects to cannabis when smoked.
A toxicologist providing advice to the Australian police, Robert Hansson, says the substance cannot be detected in preliminary workplace testing.
The makers of Kronic advise users not to attempt to drive or operate heavy machinery while under the influence.
The New Zealand Government is waiting for legislation to be passed to ban the sale of the fake drugs to anyone under 18.