Medsafe is warning that people should not drink a brand of diet coffee that has been found to contain a class C controlled drug and a prescription medicine, and says all stock of the coffee has been seized.
The medicines safety authority has tested Valentus SlimROAST Optimum Dark Roast Coffee, which comes in sachets and as powder in a tub.
The products claim to assist with weight loss and weight management, improve mood and focus, regulate blood sugar and boost circulation.
The coffee was found to contain the prescription medicine methylhexanamine (DMAA) and phenethylamine, a class C controlled drug, Medsafe says.
These substances have amphetamine-like characteristics and may have similar adverse reactions such as agitation and psychological effects, cardiovascular effects such as increased heart rate and blood pressure, and neurological effects, Medsafe says.
The authority says phenethylamine has mood and weight loss related therapeutic effects and is considered a controlled drug.
The ruling from Medsafe comes three months after 1 NEWS reported that customs was warning about health products sold online after a test of the diet coffee brand.
Methylhexanamine is known to have stimulant effects, has been associated with harm worldwide, and is banned by many sports authorities and governmental agencies, it says.
The product labels declare the presence of phenethylamine, but not methylhexanamine.
Medsafe says if you have consumed this product and feel unwell, seek medical advice and tell your healthcare professional you have consumed a product containing methylhexanamine and phenethylamine.
If you have purchased the product, return it to the point of sale or safely dispose of it.
Medsafe say it has published the warning to alert consumers of the dangers of the products as it is possible other individuals or businesses may have imported them for sale but have not been identified by Medsafe.
In July, Valentus, the company that makes the coffee and sells it through affiliates around the world, confirmed to 1 NEWS that phenethylamine is one of the ingredients in SlimROAST, and denied it contained DMAA.
A spokesperson said the coffee is labelled as not being compliant with World Anti-Doping Agency regulations because of the potential for a false positive for amphetamines.
"None of the ingredients in the coffee possess regulated drug status," Valentus said at the time.