Serial killer Ivan Milat is expected to spend a third night in a Sydney hospital after being transferred from NSW's highest security prison for medical tests.
The 74-year-old backpacker killer was transferred from Goulburn's supermax jail to Prince of Wales Hospital in Randwick on Monday afternoon.
Milat is being held in a secure annexe of the hospital where inmates are treated.
The Seven Network and ABC on Wednesday both reported Milat had cancer and wouldn't be returning to Goulburn but would likely be transferred to Long Bay Jail hospital.
The former road worker was sentenced in 1996 to seven consecutive life sentences for murdering seven backpackers whose bodies were found in makeshift graves in NSW's Belanglo State Forest in the 1990s.
He also kidnapped British tourist Paul Onions who managed to escape from Milat's vehicle.
Corrective Services NSW Commissioner Peter Severin on Tuesday said prisoner transfers were done in the "most secure and safe way possible".
High-risk and terrorism-related inmates are always guarded by specialist staff from the extreme high-security escort unit, a corrective services spokeswoman said.
"Extensive security planning and assessment is undertaken before such movements occur".
Inmates are searched before they leave prison and when they return, the spokeswoman said on Tuesday.
At least one form of restraint - handcuffs or ankle cuffs - stay on high-risk inmates during medical treatment subject to medical requirements.