The death of a young Feilding man is being investigated to find out whether it was caused by synthetic cannabis.
The 21-year-old died last Thursday after police were called to an address in Warwick St around 9.45pm.
At the same time, a number of others were admitted to Palmerston North Hospital with suspected side effects from synthetic cannabis use.
Police said it was not clear whether the death was due to use of the drug and the matter has been referred to the coroner.
But police and the MidCentral District Health Board have issued a joint warning about the prevalence of synthetic cannabis in Feilding.
They said they were extremely concerned with the amount of synthetic cannabis being used in the community.
"These drugs can be life threatening for users, who have no way of knowing what the manufacturer has used to make or modify the drug, completely blind to what they're really taking."
MidCentral DHB's acting service director for mental health & addiction services Richard Barrass said "synthetic cannabis has resulted in users exhibiting unpredictable behaviours that pose a significant risk to not only their own safety but the safety of others they may come into contact with whilst under the influence".
"As the actual toxic chemicals contained in synthetic cannabis are not known and there are frequently changes to type and quantity, the effective treatment for ingestion of what is an unknown poison is extremely difficult to assess.
"That is if the user seeks medical attention."
He said "it is therefore tragically likely that there will be more unexpected deaths among users in New Zealand as a result of the continued use of synthetic cannabis."
Police encourage anyone with information about drugs or other criminal offending to contact the local police station or call CrimeStoppers anonymously on 0800 555 111.
If you, or someone you know, is using synthetic cannabis, police urge you stop immediately and seek help if needed by contacting your local GP or by ringing the Alcohol and Drug Helpline on 0800 787 797 or text 8681 7 days a week to speak to a trained counsellor.