A man has died in custody at Shortland Correctional Centre at Cessnock, a spokesperson for Corrective Services NSW confirmed on Tuesday evening.
NSW Ambulance and a crew with the Westpac Rescue Helicopter were called to the jail around 4.05pm, however the helicopter was later called off and did not transport the patient.
Corrective Services NSW and NSW Police are investigating the incident, the spokesperson said.
All deaths in custody are subject to a coronial inquest.
"We support the coronial investigation and are assisting fully the NSW Police and the Coroner," Corrective Services said in a statement.
