The other passengers were taken to two hospitals, several with serious injuries.
Tasmanian Cancer Council chief executive Simon Barnsley said the organisation was in shock at the accident.
"Our staff and volunteers are distressed and saddened by the news and we extend our sympathies to the families of those affected," he told the ABC.
Mr Barnsley said counselling would be offered to those affected.
Acting premier Bryan Green was among the first to express his sympathy.
"I realise that at times like this words can mean very little, but I wish everyone coping with the aftermath of this crash every strength for the time ahead," Mr Green said.
Opposition spokesman Jeremy Rockliff added his concern.
"My heart goes out to the families and friends of those affected by this terrible tragedy," he said.
The Bass Highway was expected to be closed for several hours.
- AAP