Australian drug dealers are turning to underground websites to sell drugs such as cannabis and prescription drugs, according to research that reveals a surge in retailers selling drugs online.
Research by the National Drug and Alcohol Research Centre, to be released today, reveals the number of Australian retailers on the now-defunct Silk Road website more than doubled in six months - from 53 in February last year to 129 in September.
International retailers selling to Australia on the website increased 27 per cent in the same period.
Researchers found the October closure of Silk Road - dubbed the "eBay for drugs" - caused a "proliferation" of new retailers in alternative marketplaces, although many have been shut down because of security concerns.
The research found cannabis and prescription drugs were the most commonly sold drugs on underground websites, while demand for so-called "designer synthetic drugs" had declined.
In a sign of the rapidly changing market, NDARC senior research officer Joe Van Buskirk said there were at least 10 more markets on the "dark web" even though two websites, BMR and Sheep Marketplace, which opened after Silk Road's closure, had been shut down.
He said the research suggested the online marketplace was mirroring the "traditional street market" rather than representing a new marketplace.
Among domestic retailers, MDMA, cannabis and pharmaceuticals were the most commonly sold substances on Silk Road.
Mr Van Buskirk said the research involved "surface web monitoring", which included sites registered with search engines as well as the "dark web", which required specially configured data.
Underground drug websites are believed to have been linked to a number of deaths, including the death of Perth teenager Preston Bridge, who died in a balcony fall after taking synthetic LSD.