"Buying drugs on the Internet is really easy," said Daniel Altmeyer, an Interpol officer addressing the World Forum Against Drugs.

"You only need an Internet cafe, a credit card, and it's done."

"It's a new kind of audience, helping new people to try many new things."

The distributed nature of the internet makes it harder for law enforcement agencies to clamp down on the drug trade.

"The crime doesn't take place in the machine," Altmeyer said.

"A website may be hosted in Sweden, but the drug will come from Latin America and will be shipped by boat to South Africa, with dealers spread out across Europe."

"It's a global network."

Another factor driving growth in drug trafficking on the internet is the ability to preserve privacy.

"You feel safe because it's anonymous," said Krister Gaefvert, a police inspector in Sweden.

"There's this feeling of being anonymous behind your screen...It doesn't always feel illegal."

But the corollary is that users are taking chances when dealing with people they don't know.

"With traditional trafficking, you knew your dealer, you knew where the drugs came from," Gaefvert said.

"Here, you don't know anything."

Around 90% of the illegal drugs traded on the internet are in fact pharmaceuticals.

"You find a lot of products with some comments from fake specialists and photos of people wearing a white lab coat," said Gaefvert.

"The purpose is to look very serious, just to make the client think that he's not doing anything illegal."

Drug enforcement is further complicated by the fact that a substance may be illegal in one country, yet it can be legal in another.

One example is ketamine -- while it is illegal in many countries, it is legal in India.

"If I find this website in India, even with the best laws in Sweden, Germany or the United States, they can send me as much ketamine as I want by post," said Altmeyer.