Customs is monitoring international websites that sell illegal drugs and cracking down with prosecutions.
A man was prosecuted in Christchurch this month for buying drugs through the Silk Road website and was sentenced to 18 months supervision.
Investigations Manager Mark Day said some people are quite adventurous in how they get drugs sent into New Zealand, but Customs' international mail centre is well equipped to keep track of any suspicious parcels.
Mr Day said about 10 cases are currently going through the courts.
Earlier, the Drug Foundation said websites selling illegal drugs pose a challenge to Customs agencies throughout the world.
The foundation said the website has a similar format to trading sites such as Trade Me and Amazon and is used by buyers and sellers all over the world.
Executive director Ross Bell said border agencies such as Customs will find it difficult to locate drugs bought online because they are sent frequently and in small quantities.