Customs is intercepting more mail containing cocaine, LSD and Ecstasy as people use online drug marketplaces to order recreational drugs.
Such websites have seen a "steady flow" of mail containing drugs being sent to New Zealand, Customs says, and the rise in interceptions is partly due to better identification of signs a package could contain drugs.
It warns those who feel a sense of anonymity ordering drugs online - often through encrypted software and using hard-to-trace Bitcoin - face the usual penalties.
"We accept that a large number of people importing over the internet are importing for their own personal use, and that is without question," said Bruce Berry, Customs' manager of cargo operations.