Bell became one of the most notorious murderers in New Zealand history when he callously gunned down William Absolum, 63, Mary Hobson, 44 and Wayne Johnson, 56, during a robbery at the RSA on December 8 2001.
Bell left the mother-of-one for dead with broken arms and severe head injuries that caused a stroke.
She lost about 80 per cent of her blood and ambulance officers later said she came as close to dying as she could get.
Corrections confirmed a contraband DVD was found in an inmate's cell but refused to name Bell.
However two prison sources have confirmed it was him.
"The DVD had been modified to appear as a regular commercially produced music CD," Auckland Prison director Andy Langley told the Herald on Sunday.
"Prisoners are able to have up to 12 commercially issued CDs issued to them as part of their authorised property."
Langley said the DVD player was given to him during a lunchtime lock up period "to enable him to watch a DVD which was part of a programme he was taking part in".
"He was charged with an offence through the internal misconduct system for being in possession of contraband, and pleaded guilty," he confirmed.
Langley said the find had resulted in changes to the rules around DVD players for all inmates in the maximum security prison at Paremoremo.
"Any DVD content that needs to be displayed will now occur in an education room with staff supervision," he said.
"Staff have also been reminded that every disc entering the prison must be checked for legitimacy, even if it does not appear to have been modified or doctored."
Langley said a "range of methods" were used to prevent contraband from entering prisons.
"They include extensive prison perimeter security, camera surveillance in visit rooms and other areas, searches of prison visitors and staff, the use of scanners and x-ray machines at entry points, checks of incoming prisoner mail and property, and use of specialist detector dog teams.
"Prisoners in possession of contraband, or those found to be introducing it into a prison, will be held to account," he said.
A prison source said it was initially suspected that Bell was able to smuggle the porn into the prison through his job in the kitchen.
He was stood down from that job while the find was investigated.
Although he was taken to North Shore Hospital for treatment, he was back in the prison early the next day.
In December 2007 Bell was attacked by another inmate after he made derogatory comments about his victims.
Convicted murderer Dean Shepherd set upon Bell while the pair were alone in a telephone room at Auckland Prison in December 2007.
Shepherd - serving a life sentence for the 2004 murder of his landlady - told a probation officer he stabbed Bell with a sharpened piece of steel from a ring binder because he was sick of hearing him talk about his crimes.
He was sentenced to 10 years in prison for the attack on the triple murderer, to be served concurrently with his life sentence.