There's evidence New Zealand could be experiencing a problem that's alarming German officials, the so-called "stoned grandparent'' phenomenon.
Germany has seen the number of pensioners convicted of drug offences double in the last decade in some regions.
But in the same period in New Zealand, crime statistics showed the number of over-51s arrested for drug possession tripled.
The Foundation for Alcohol and Drug Education's executive director, Colin Bramfitt, said it was a worrying international trend.
He said that older people were often on medications which, combined with illegal drug use, may cause problems.
Mr Bramfitt said a government-led publicity campaign could be beneficial.
- NewstalkZB