Three years after man dies in struggle with prison guards, most staff still not trained

Almost three years after Aboriginal man David Dungay died in custody most NSW prison staff have still not received physical training on the dangers of positional asphyxia.

Mr Dungay died after a struggle with guards in his Long Bay prison cell in December 2015.

He was restrained facedown by at least five officers in the "prone" position, and was forcibly removed from his cell because he wouldn't stop eating biscuits.

He screamed "I can't breath" before becoming limp and vomiting. The 26-year-old couldn't be resuscitated, a coronial inquest into his death heard earlier this year.

At a budget estimates hearing on Tuesday, Corrective Services NSW Commissioner Peter Severin admitted just a few staff had recently begun physical training regarding the dangers of positional asphyxia.

"The physical training, where we actually take the staff through the physical aspects of the application of those techniques, has not commenced until very recently," Mr Severin told the legal affairs hearing.

Further quizzed on how many officers had received physical training, Mr Severin took the question on notice.

He said relevant officers had received some written advice concerning positional asphyxia "pretty much straight away" following Mr Dungay's death.

Greens MP and committee member David Shoebridge says the delay in providing adequate training suggests a "systematic failure" in the NSW prisons system.

"It's a matter of life and death and it hasn't been addressed," Mr Shoebridge told AAP.

But a Corrective Services spokeswoman later said a 2016 investigation into Mr Dungay's death had prompted many changes in policy and training procedures.

"Extensive consultation occurred between Custodial Corrections, Security and Intelligence and Justice Health in relation to policies and procedures relating to the use of force on inmates," the spokeswoman told AAP in a statement.

"We have also developed a new training course for all officers involved in the use of force on inmates. It ... includes training on how to avoid the risk of positional asphyxia."

The spokeswoman said the course was currently being rolled out to immediate action teams. IAT officers were involved in Mr Dungay's death.

The two-week inquest into Mr Dungay's death, which opened on July 16, planned to get through an ambitious roster of 28 witnesses, however questions and cross-examinations took longer than anticipated.

Eight witnesses are still yet to be interviewed, and the inquest was postponed for eight months, due to recommence in March 2019.

Mr Dungay's mother Leetona Dungay said the inquest had opened wounds and it was "devastating" to hear she would have to come back.

"I hoped and prayed for closure from this inquest, but now we have to wait another year in our fight for justice," Mrs Dungay said at the time.

"I'll be patient. I won't give up, I'll keep strong."

She said she hoped the inquest would eventually bring change throughout the corrective and justice health system so that "no mother or family have to watch their loved one die" the way she has had to.

AAP