Glenn Richard Albert Mills was found dead overnight in his cell at Auckland Remand Prison at Mt Eden, a day before he was due to reappear at Auckland District Court.
The Department of Corrections said his death was not regarded as suspicious and that it had been referred to the coroner.
Mills, 40, a train driver who had been in custody for several months, faced 28 charges in Auckland District Court relating to 14 people.
The charges included wounding and attempting to wound with reckless disregard and infecting and attempting to infect with a disease.
Seven of the 14 people whom Mills was charged in connection with - 11 men and three women - were believed to have contracted the HIV virus.
Body Positive chief executive Bruce Kilmister said he had mixed feelings over the news of Mills' death.
He said the premature death of an HIV sufferer was sad but it would spare victims and their families from having to give evidence before the court.
"That's the only positive aspect we can see. It will avoid any long trial and won't put any people through that ordeal."
Mills was first arrested on a charge of infecting three men with HIV and attempting to infect a fourth.
News of his arrest and his subsequent naming led to many more people coming forward for HIV tests, and led to the charges relating to more people.
Mr Kilmister said Body Positive tested more than 50 people once Mills had been named.
With his death coming the day before World Aids Day, Mr Kilmister said it reinforced the message that people needed to continue to test themselves and to practise safe sex.
"Each person has a responsibility to keep themselves and others safe from the transmission of this virus."
He said public attitudes towards the disease had made some progress but there was still some stigma towards people with the disease.
The Crown had been seeking an order to force Mills to supply a DNA sample as the case got closer towards a possible trial.
Department of Corrections assistant regional manager Grace Smit said little official comment could be made while an investigation and the coroner's inquest was pending.
"Staff provided medical assistance but were unable to revive the prisoner. He was pronounced dead when ambulance staff arrived a short time later," Ms Smit said.
"The prisoner's death is not considered suspicious. However, the coroner will investigate and confirm the circumstances."
She said a review of Mills' death would be undertaken by the independent Corrections Inspectorate, which is monitored by the Office of the Ombudsmen.
"While this is under way, and the death is subject to the coroner's inquest, the department is unable to comment further."
