New Zealanders seeking treatment online for erectile dysfunction were the main group uncovered in a bust on the illegal trade of medicines.
A week-long sting by Medsafe and Customs uncovered 181 packages entering New Zealand which required further investigation because they contained prescription medicines, weren't labelled, or were known to contain undeclared or hidden ingredients.
Medicines for the treatment of erectile dysfunction were the most prevalent products examined by Medsafe - with 3412 individual tablets examined.
Medicines for insomnia, treatment of infections, mental health and pain were the next most prevalent.
Four parcels contained a counterfeit or fake product - all of which were for the treatment of erectile dysfunction. Last year, only two counterfeit or fake products were found.
The sting was part of an Interpol-led operation called Pangea VIII which aimed to disrupt criminal networks trading in illicit, counterfeit and poor quality medicines through working with international and national enforcement bodies, and internet and payment system providers.
The parcels investigated came from 29 different countries. More than 100 were from India, while 24 were from the United States, and 20 were from China.
Derek Fitzgerald, Medsafe manager of compliance management, said medicines purchased online were risky because quality, safety and effectiveness weren't guaranteed.
"Consumers considering buying any type of medicine over the internet should be aware that, even though a website may appear to be legitimate, appear to be established in a well-regulated country, and appears to be offering well-known medicines, these impressions may not be true," he said.
Medsafe encouraged anyone intending to buy prescription medicines online to consult their doctor who could advise on potential side effects, interactions with other medicines and appropriate dosage, he said.
"Prescription medicines are potent substances and as such should only be used following a consultation with a doctor."
Most prescription medicines Medsafe detained were held until the person importing them provided a valid doctor's prescription, he said. If this didn't occur they were destroyed.