Customs warns users who buy online after increase in intercepted packages.

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.

Advertisement

"But the big message to them is they run the same risk as somebody who straps those drugs to their body. The charges are importation. It carries 14 years [imprisonment]."

Customs information on interceptions through mail centres for the last three financial years shows big increases for some drugs.

Cocaine catches increased from five in 2011/12 to 54 in 2013/14, LSD from three to 85 in the same period, and Ecstasy from 85 to 139.

Mr Berry said the interceptions were generally smaller amounts, and did not indicate a similar increase in overall quantities being seized across all entry points to the country.

About 2.4 million items of mail come into New Zealand every month. However the proliferation of websites for ordering and posting drugs was a concern, he said.

"Cocaine particularly is more the smaller importations by a user-consumer ... And the same is reflected in the [Ecstasy] space.

"Meth volumes are reflective of organised criminal groups utilising a different stream to try and bring smaller quantities into the country as opposed to larger importations."

In February, a US court convicted Ross Ulbricht, 30, on charges of creating the website Silk Road, a multi-million-dollar marketplace for illegal drugs and other contraband that offered users anonymity by operating on the so-called Tor network, which masks computer locations.

Mr Berry said he understood Silk Road remained shut, but similar websites had sprung up.

A planned overhaul of the Customs and Excise Act partly designed to help Customs deal with changes in technology is not far away.

Customs wants changes including requiring a person to provide a password or encryption key to their electronic devices.