Mark Lyon, a former property millionaire who was jailed for drugs and sex offences died over the weekend, New Zealand Herald has reported.
Corrections confirmed to Newshub a prisoner had died, but wouldn't confirm the identity.
"A man in custody at Tongariro prison passed away on 29 July, while being cared for in hospital.
"The man was transferred to Waikato Hospital on 24 July," Tongariro prison director Megan Tuhoro told Newshub in a statement.
Lyon, an Auckland property developer, was jailed in 2014 on drug and sex charges and was serving a 15-year sentence during his death.
In 2020 Stuff reported Lyone was hooked on meth and would swap the drug for sexual services, including from underage girls.
He reportedly sexually assaulted young women in a dungeon-style room in central Auckland.
Tuhoro also said in the statement: "As the man’s death remains subject to investigation, and the Coroner is yet to determine the cause, we are limited in the amount of detail that we are able to provide."