The government is being warned that detaining asylum seekers in prison is dangerous, and it is just matter of time before someone takes their own life.
About 10 asylum seekers are being held at Mt Eden and Waikeria remand prisons and one has been behind bars since March last year.
Immigration New Zealand said all asylum seekers in remand were there because of concerns they posed a potential security risk. It said the majority of asylum seekers were not detained in prisons.
However, Amnesty said they had committed no criminal acts in New Zealand. In some cases they had been assaulted by other prisoners.
Auckland lawyer Deborah Manning said she had represented most of the asylum seekers who had been detained in Mt Eden prison.
Her clients were vulnerable and it was no place for them, she said.
"Clients come to New Zealand full of hope, feeling as though they've finally found a safe place and they're put into Mt Eden, which is frankly a hell hole...
"As time goes by, they become more and more desperate. Some become as desperate as you can get and I even had a client try and take their own life," she said.
The government needed to look at alternatives to Mt Eden prison such as electronic monitoring or hostels, Ms Manning said.
Auckland lawyer Richard Pidgeon represents two asylum seekers from India detained in either Mt Eden or Waikeria remand prison in the Waikato.
He said his client in the Waikato had been detained since March last year but was not guilty of any crime.
Mr Pidgeon said the man was being treated as a criminal and was subjected to standover tactics from other prisoners.
"Torture is psychological and physical... He's having his issues compounded by what in effect is a lower level of torture."
Mr Pidgeon agreed that courts should release detained asylum seekers on electronic monitoring.
"A lot of the people I act for have traumatic experiences from their homelands and it's just exacerbated when they're put in a prison environment.
"A district court judge can release a detained asylum seeker on any condition so logically electronic monitoring could be one of them."
Alan Whitley is the national president of the Corrections Association, which represents prison guards.
Mr Whitley said the government might need to look at building a separate facility within the prison system, just for asylum seekers, given New Zealand's prison muster was creeping up.
In a statement, the Corrections Department said it was particularly mindful of the circumstances of asylum seekers being held in prison and made every effort to ensure their safety.