A Police Drug Intelligence report shows drug trafficking by Kiwis who use the dark web is booming and illegal seizures at the border show no sign of slowing down.

The confidential report, obtained exclusively by Newshub, says Internet-facilitated drug trafficking has "increased exponentially" around the globe.

Drug seizures at the international mail centre have more than doubled in the past five years.

The top three items bought by Kiwis online are cannabis seeds, MDMA and prescription medications. They're sourced mainly from the Netherlands, the UK and Canada.

The drugs come daily, and in small amounts.

"It means for Customs, they're not looking for the big bust," says Drug Foundation executive director Ross Bell. "They're having to look through hundreds of thousands of envelopes."

MDMA seizures are up significantly - about 8.7 kilograms were found in 2016, split across 706 different items of mail. That number shot up to 13 kilograms last year and that's just what was detected.

"Much more of that drug would have got through and be distributed all through New Zealand," says Associate Professor Chris Wilkins from SHORE & Whariki Research Centre.

"The seizures we are looking at are just a tiny proportion of the market, so that really is concerning."

Some 8100 NBOMe tabs - a highly potent hallucinogen which has led to deaths overseas - were destined for Hastings in 2016. That represented two thirds of all NBOMe found that year.

"That is a significant amount," says Customs Intelligence Officer Wei-Jiat Tan

"It could be that while the drug is being sent to a place like Hastings, it could end up being for onwards distribution to other parts of the country."

In the same year, most MDMA powder was headed for homes in Christchurch and when it came to finished MDMA pills, Queenstown topped the list with 2085 tablets - surpassing even Auckland by 700 pills.

"I think it just represents that Queenstown is this international party location destination for tourism from all over the world," says Professor Wilkins.

While not every seizure will lead to an arrest, Customs warns plenty of information can be gleaned from the post.

Last year, the FBI shut down AlphaBay and Hansa Market - two of the largest dark net marketplaces in the world.

The report notes while that may mean a temporary lull in drugs trafficked to New Zealand, "it's inevitable that [other sites] will emerge."

If you have more information, you can contact Michael Morrah in confidence at michaelmorrah@mediaworks.co.nz

Newshub.