The Justice Department confirmed the death due to "apparent natural causes" but did not reveal his identity.

However, The Examiner confirmed with several well placed sources that Carr died in the Royal Hobart Hospital.

The sources said the death was not suspicious.

Carr, who was about 50, was serving a 23-year sentence for the stabbing murder of a 62-year-old Ravenswood resident in 2009.

Carr was found guilty of the murder after a trial in Launceston's Supreme Court the following year.

Robert Porter was stabbed 10 times in the head, neck and back by Carr.

Mr Porter, who suffered several disabilities, was trying to protect a woman being threatened with a knife by Carr at the time.

The career criminal served numerous jail terms starting in 1981 when he turned 18.

"The Tasmania Prison Service extends condolences to the inmate's family," a Justice Department spokeswoman said.

"The department is not able to comment further as the matter is the subject of a police inquiry and examination by the coroner, which is standard practice in the corrections environment, even in cases when the death appears to be from natural causes."