Allegations of fighting inside prisons have been around for years and have been investigated but nothing could be proved, a former Corrections Minister says.
But Anne Tolley said she had never heard of a practice of dropping prisoners from balconies.
Investigations are being conducted into reports of prisoner violence and the death of a prisoner after allegedly being dropped from a balcony at Mt Eden.
Labour's corrections spokesperson Kelvin Davis has claimed Nick Evans was dropped by other inmates at the remand prison in May, and later died in hospital from a ruptured lung.
Ms Tolley, now Social Development Minister, was Corrections Minister between 2011 and 2014.
"I heard lots of crazy things from the union who hate the private prison, none of which were substantiated, none of which they're able to provide any proof of," she told Morning Report.
"But I have never heard that term dropping, I've never heard of people being pushed."
She said if prisoners had been dropped over balconies, quite significant injuries would have been reported.
The day-to-day running of the Auckland prison was outsourced to facilities management company Serco in 2011.
Serco's 10-year-contract with the Government to run Mt Eden Prison has six more years to run.
Claim prison fights go back three years
Radio New Zealand has been told organised fights have been going on at Mt Eden prison for more than three years, and used to be known as 'The Contender'.
An experienced criminal lawyer said previous clients had confided in him that new inmates were given no choice but to fight.
The lawyer said one of his clients was hospitalised after a 'contender' bout, but the prisoner refused to let him raise the fights with authorities because he was afraid of being labelled a nark.
Death never made sense - family
The family of a Nick Evans say they not believe the circumstances of his death add up.
His father, Glen Evans, who lives in Auckland, said his son was 6ft tall and healthy and it did not make sense for his lung to have ruptured for no reason.
He said the family was not ready to speak about his son's death, but what they had been told about how he died never made sense.
The family is now deciding what steps to take next to try to find what happened to their son