A "huge" security operation is underway after Australia's most notorious serial killer, Ivan Milat was released from prison on Tuesday.
WATCH: How they pulled off the secret operation to treat Ivan Milat in hospital
The 74-year-old was taken from Goulburn’s Supermax Prison to Sydney’s Prince of Wales Hospital this afternoon where he is undergoing treatment for an undisclosed medical emergency.
"The transport operation was a logistical feat for authorities who left nothing to chance," Seven News' Evan Batten reported.
"It was so secretive that not even the government knew about it until told by Seven News."
NSW Police say the backpacker serial killer is under 24-hour surveillance to ensure the safety of the Australian public, hospital workers and patients.
The security detail that transported him to hospital drove right past the Belanglo State Forest where he murdered and buried his victims.
He was convicted of seven murders which he committed between 1989 and 1993.