The Mercury understands Michael Black, 33, was waiting in a designated pod inside the privately-run prison ahead of a scheduled appearance in Wollongong Local Court when he was stabbed just before 12.30pm.

Emergency services were called to the jail but were unable to save Black and he died at the scene.

Officers from Quakers Hill Police Area Command established a crime scene and detectives have launched an investigation into the circumstances surrounding the incident.

Michael Black was well acquainted with jail life, having spent two years behind bars in 2013 after pointing a loaded gun at a police officer following a dangerous police pursuit.

In January this year, Black was charged with concealing a shooting that occurred in broad daylight near Dapto Public School. It was alleged he and another man, Rhian Kinloch, went to Derek Ferguson's Denham Drive home on November 15 and spoke with him through the front door.

Moments later, Ferguson allegedly pulled out a silver pistol and shoot three rounds at the duo, causing them to flee.

Black was arrested in January and charged with concealing a serious indictable offence of another.

He was released on court bail at the time but was arrested again in February accused of carrying out an armed robbery at the Berkeley Post Office.

He had been due to appear in court via video link from Parklea prison today on the robbery charge however his lawyers advised the court about 3pm that they had been unable to contact him because the jail had been "placed into lockdown".

A reason for the lockdown was not provided at the time, however police issued a statement at 5pm advising of the fatality at the centre.

Meanwhile, MTC-Broadspectrum, the company that runs the prison, released its own statement extending its "deepest sympathy" to Black's family and saying it would fully cooperate with police during the investigation.

"He received immediate treatment by St Vincent's health staff before paramedics arrived on-site. He passed away just before 1pm today," a spokesperson said.