The mother of a New Zealand-born man who was in detention in Sydney says neither the Australian authorities nor lock-up operator Serco called the family on the day her son died.
In findings released this afternoon, the New South Wales coroner said Robert Peihopa, who had been detained on criminal convictions, died from a heart attack.
She found he had chronic heart disease, had taken methamphetamine just hours before, then experienced "physical and emotional distress arising from his involvement in a fight immediately prior to his death".
His collapse was caught on security cameras but Serco guards did not respond for 17 minutes.
The coroner's inquest in September had heard that an autopsy found the 42-year-old died in April last year from methamphetamine toxicity complicating a serious heart condition.
Coroner Teresa O'Sullivan asked officials to review whether two guards on duty in the unit was enough supervision.
The coroner said the New Zealander collapsed and died in full view of a guardhouse after a fight.
"I reject the submission from Serco that Mr Peihopa collapsed in a 'blind spot,'" she said.
Two guards were supervising 60 men in the unit at the time, around 9.30pm. They were probably "spread too thin" to spot Mr Peihopa collapse, though it was caught on security cameras, or the other detainees trying to pick him up.
Australia's Immigration Department and private operator Serco need to review staffing, said Ms O'Sullivan.
She also suggested setting up a rehabilitation programme for detainees who use meth.
"The Department [of Immigration] and Serco should review their procedures to facilitate greater sharing of information about suspected drug and alcohol use by detainees with staff members who have supervision or welfare responsibilities towards those detainees," she said.
Originally, his family suspected he had been a victim of foul play in immigration detention.
His mother Hera said nobody who was supervising her son in the Villawood lock-up "had the slightest understanding about what is required to supervise and care for the health and welfare of detainees".
Mrs Peihopa said no one from Serco or the Immigration Department had contacted her on the night her son died.
"Since Robert's death not one person from Serco or the Department has called me or spoken to me or written to me to say they were sorry about Robert dying on their watch.
"My son was dead inside Villawood and all I got - all my family got - was arrogant indifference shown by Serco officers and the Department."
Robert Peihopa was on the deportation list after serving a jail term for reckless driving under the influence of drugs.
"I think it is a terrible injustice that Robert was placed in Villawood Immigration Detention Centre at all. After all, he was virtually an Australian," Mrs Peihopa said in a statement.
He had been living in Australia from the age of 17.
Mrs Peihopa called on Australian Prime Minister Malcolm Turnbull and his New Zealand counterpart Jacinda Ardern, "to sit down and stop this crazy situation" of New Zealand citizens being detained in large numbers.