High profile human rights lawyers Geoffrey Robertson QC and Jennifer Robinson want to bring the death of NSW Indigenous man David Dungay Jr in custody in 2015 to the attention of the United Nations.
Mr Robertson, Ms Robinson and Mr Dungay's mother Leetona and nephew Paul Silva aim to bring Mr Dungay's case "to the international community" in the wake of the global Black Lives Matter movement, galvanised by the 2020 death of George Floyd Jr at police hands in Minneapolis in the US.
Mr Floyd's death at the time sparked global protests.
They also accuse the NSW government of failing to hold those responsible for Mr Dungay's death to account.
Ms Dungay will make a complaint to the United Nations Human Rights Committee, arguing the NSW government failed to protect her son's right to life.
She will also raise the failure of Australian governments to implement all the recommendations from the 1991 Royal Commission Into Aboriginal Deaths in Custody.
"My son had a right to live. He had the right to be safe from harm," Ms Dungay said in a statement.
"I have the right to demand accountability and justice for what happened to David.
"The government and the prison had a duty of care to keep David safe, with people who were trained properly to keep him alive. The system failed and David lost his life because of that failure."
A 2019 coronial inquest into the 26-year-old's December 2015 death at Long Bay jail found the prison officers involved were not motivated by malicious intent.
But Mr Dungay, a diabetic, died at the jail's hospital after being restrained in his cell because he refused to hand over a packet of biscuits he was eating.
Footage played during the inquest showed Mr Dungay repeatedly screaming "I can't breathe" to which one officer replied: "You're talking, you can breathe."
Mr Dungay was restrained by five prison officers and pinned down on the bed, and was seen spitting blood as he was taken from the cell.
After being placed in a second cell, he was injected with the sedative midazolam but died an hour after officers first entered his cell.
"The Australian government has obligations under international law to protect the right to life and to prevent deaths in custody," Ms Robinson said.
"Yet Australia has failed to implement recommendations from both the Royal Commission and UN bodies to prevent deaths in custody.
"As a result, 30 years on from the Royal Commission, the rate of First Nations deaths in custody remains unacceptably high, with at least five deaths already in 2021."
Australian Associated Press