An international crackdown led by Interpol has picked up more than 170 packages of illicit prescription medicines coming into New Zealand, in one week.
The government's medicine safety authority, Medsafe, which ran the local operation with Customs, said the parcels from 31 different countries were picked up because they contained prescription medicines, were not labelled or contained undeclared or adulterated ingredients.
Medsafe compliance manager Derek Fitzgerald said treatments for erectile dysfunction were the most common, followed by medicines to treat infections, heart disease and pain relief.
"It's quite easy to sit in front of a computer and use your credit card and purchase something," he said.
"They may not realise that it's not legal for them to purchase prescription medicines over the internet and bring them into New Zealand, but certainly when they're detected at the border they receive something from us that tells them all about the hazards involved in doing that.
Mr Fitzgerald said such drugs were risky because their quality, safety or effectiveness could not be guaranteed.
Every year, Customs intercepts between 10,000 and 12,000 illegal imports of prescription medicines.