A southern Tasmanian man has pleaded guilty to trafficking a controlled substance, following what the police have called the biggest drugs bust in the state's history.

Nicholas Mark Stebbins trafficked drugs including amphetamines, MDMA and cocaine with an estimated street value of $11m between August 2012 and July 2014 – and paid for them with bitcoin.

Hobart's Supreme Court

heard that Stebbins helped arrange and pay for seven parcels filled with drugs to be posted to Tasmania from overseas.

Crown prosecutor Darryl Coates said that the parcels, which were intercepted in Tasmania, Western Australia and Victoria, collectively contained more than 2kg of amphetamine and about $500,000-worth of MDMA.

Defence lawyers told the court that while Stebbins was part of a group that imported drugs, he was "certainly not the head" of the operation.

Stebbins is currently in custody and is awaiting sentencing next month.

The bust was part of a bigger police operation involving Tasmania Police, the Australian Federal Police and Australian Custom officers.