A new anonymous internet marketplace for illegal drugs has opened, with the same name and appearance as the Silk Road website shut down by US law enforcement authorities a month ago.

Like its predecessor, the new Silk Road listed hundreds of advertisements for controlled substances available to buy using the anonymous Bitcoin digital currency.

On October 1, the Federal Bureau of Investigation shut down the original Silk Road and arrested its alleged mastermind, Ross William Ulbricht, 29, known online as "Dread Pirate Roberts", in San Francisco.

"It took the FBI two-and-a-half years to do what they did...but four weeks of temporary silence is all they got," a site administrator wrote, also using the "Dread Pirate Roberts" pseudonym, when the site opened on Wednesday.

A new Twitter account was also launched in conjunction with the site's re-emergence.

Multi-million dollar marketplace

The FBI declined to comment on the new version of the Silk Road. For more than two years, the original site allowed users to buy and sell illegal goods and services on the assumption that they were safe from the law.

Deliveries were made through the mail in discrete packages. US authorities also say Ulbricht had tried to have a user who had threatened to expose the identities of thousands of Silk Road users killed.

The charges against Ulbricht said his website generated sales of more than 9.5 million Bitcoins, roughly equivalent to $1.2 billion.

The new website uses improved technology meant to keep identities secret, including measures to keep users from losing their Bitcoins in case the site shuts down, according to the new Dread Pirate Roberts.

Like the original Silk Road, users access the new site using a no-cost, anti-surveillance service known as the Tor network instead of traditional web browsers.

"The Silk Road has risen once more...Open communication with your old suppliers and customers, let this wonderful news be taken to all corners of the Tor Network and beyond," the new administrator wrote.