Prominent Australian right-to-die campaigner Philip Nitschke says the shutdown of black market website Silk Road will have a devastating impact on people who use it to obtain euthanasia drugs.

Last week US authorities busted the online bazaar for drugs, arresting the suspected mastermind Ross William Ulbricht, also known as "Dread Pirate Roberts", in San Francisco. His attorney has denied the charges.

Silk Road is the Amazon of the drug trade.

Nitschke, the head of Exit International who has campaigned on euthanasia issues for more than a decade, said a lot of people used the marketplace to source reliable quantities of the premier end-of-life drug Nembutal.

Information about how to purchase the drug on Silk Road was contained within The Peaceful Pill Handbook, which is published by Exit International and banned in Australia, but which is available online as an e-book. The information on obtaining the drug through Silk Road would now be removed and replaced with a screen grab of the FBI take down notice which now appears on the website, Dr Nitschke said.