Three intellectually disabled men who say they were mistreated while detained in state care are suing the government for up to $1.4 million.
The case opened in the High Court in Wellington this morning.
Human rights lawyer Tony Ellis is representing the men, while the Waitemata and Capital & Coast District Health Boards and the Attorney-General are among the five defendants.
The men have name suppression.
Mr Ellis told the court there was little legal precedence on the subject and highlighted the importance of the case.
The men are seeking a lump sum of up to $300,000, and an additional $25,000 for every year each has been detained.
One of the men has been detained since 1999, one since 2002, and the other from between 2001 and 2014.
All three previously came before the courts on unknown charges before detention.
Mr Ellis said a declaration from the government that there had been mistreatment was more important than any monetary amount.
In his opening remarks, he said the men's human rights had been breached and they had been "warehoused", or "put on a shelf and forgotten about".
"That means they're not being provided with proper care," he said.
The claim also includes allegations of unnecessary and systemic use of medication, unnecessary use of restraints, unreasonable solitary confinement or 'seclusion', and medical experimentation.
Mr Ellis told the court that, in seclusion, his clients did not have immediate access to a toilet without asking permission, and one of the men was seriously injured while he was restrained.
He said they were not allowed much in the way of possessions, were often prevented from communicating with the outside world and were subjected to regular unlawful searches.
The hearing is expected to last about six weeks.
Spotlight on seclusion
Last month, a report from the Chief Ombudsman found an autistic man, Ashley Peacock, who is not involved in this case, should not be held in seclusion in a mental health unit in Porirua.
It said the conditions were akin to torture.
However, Associate Health Minister Sam Lotu-liga said the Ministry of Health had reassured him Mr Peacock was being cared for in the best possible way.
The Capital & Coast District Health Board said seclusion was used as an intervention as a last resort when necessary to maintain safety.
The board said no one lived permanently in seclusion.