The use of electric shocks as a method of controlling and subduing young people at Lake Alice Psychiatric Hospital in the 1970s has been described as nothing short of torture to the Royal Commission of Inquiry into Abuse in Care.
The hearing over the next two weeks is examining how children, some as young as eight were given electroconvulsive therapy, not for any medical reason, but mainly as a punishment and often without anaesthetic.
Between 1972 and 1978, it is estimated up to 300 young people went through the Child and Adolescent Unit at Lake Alice.
Inquiry lawyer Andrew Molloy said the figure could be at least 100 higher because records have never been found.
"Children were subjected to abuse, including sexual abuse while at the unit. Some staff were among the perpetrators, sometimes the children fell victims to older and bigger children, and sometimes to adults housed at the main Lake Alice Hospital."
The abuse was masked in the terminology of orthodox therapeutic interventions, when in fact they were nothing of the sort, he said.
It all happened under control of lead psychiatrist Selwyn Leeks.
"You will hear of a behavioural modification programme implemented by and under Dr Leeks imposed somewhat misleadingly in the guise of aversion therapy. This also revolved around the application of electric shocks to the body. The head, the limbs and even the genitals.
"No anaesthetic was administered before the administration of those shocks."
Lake Alice survivors' lawyer Frances Joychild QC described it as a dark and shameful seven-year episode in the history of state care of vulnerable children.
"They were dealing with a situation of systemic and extensive child torture extending over a number of years."
The abuse was not restricted to electric shocks, she said.
"They received intensely painful injections and drugs. Sometimes locked up alone for days or weeks and subjected to sexual assault in all its forms. Those who avoided some or all of these afflictions lived nevertheless in an atmosphere of terror, where they witnessed the fear and misery of others and waited for their turn."
No one has ever been held to account over what happened at Lake Alice, including Leeks, who was in charge of the child and adolescent unit.
He left New Zealand for Australia not long after the unit closed in 1978.
His lawyer Hayden Rattray spoke to the inquiry via an audio link from Melbourne.
Leeks was designated a core participant in the inquiry in April 2021 and he was assessed by a euro-psychologist in March 2021.
Rattray said Leeks was 92 years old and not in good health.
"As a core participant Dr Leeks has the right to give evidence and make submissions, but he is by virtue of his age and cognitive capacity is manifestly incapable of doing either.
"Dr Leeks is neither aware of the matters before the inquiry nor cognitively capable of responding to it," Rattray said.
"In reality I represent a man who is incapable of instructing me."
Niuean Hakeagapuletama Halo spent two periods in the unit starting at the age of 13.
His first electric shock knocked him out cold and he did not feel a thing, but the second time was different.
"I'd say it was really painful."
He said Leeks put electrodes on his temples.
"Another thing he always does is wet it, the ends with water."
Halo said without a mouth guard he would have bitten of his tongue, as the pain was intense.
"When they turned it on I could feel myself actually sitting up or the body is off the bed. Your arms out the front or you and straining to fling your arms, but they are holding you down. They turn it off and that's when you fall back down and you are crying and he turns it back on again and it goes on or whatever until you are knocked out and that is when it stops."
Halo ended up having 10 electric shock treatments.
He told the inquiry he could not remember why he was being punished and that he begged Leeks to stop.
"He would say, 'I'm sorry but it has to be done'."
He said Leeks used to call him an uncontrollable animal.
Halo was asked what his reply would be now.
"I would turn it back on him. He's just talking about him. The way he treats us."
Halo is the first of 18 survivors of Lake Alice who will give evidence to the Royal Commission over the next two weeks.
There will be a total of 40 witnesses, including medical professionals, police, and the Solicitor General.