Australians are now regularly buying drugs online from vendors who go by aliases such as "PostmanPot" – and the government is yet to figure out how to stop them.

The existence of Silk Road, an anonymous online marketplace functioning as a kind of eBay for illegal drugs and other contraband, was first reported in June. But now Australian sellers are trading regularly on the site. Online records show they have made more than 100 sales of drugs such as marijuana, magic mushrooms and a range of pharmaceuticals, and sales are increasing daily.

A picture of novocaine's stash.

The government's mandatory internet filter, which is now on the backburner, could have been used to try to force ISPs to block the site, but even that is unlikely to be effective. As it stands there is no way to prevent Australians using it and police say the site is beyond their remit because it is hosted overseas.

PostmanPot is the collective username of a group of Australians - "no more than seven" - selling marijuana in small quantities on Silk Road. "All of us have experience selling afk (away from the keyboard)," one member of the group said via a private message on the Silk Road website.