An emergency care specialist says he believes NSW police failed in their duty of care towards a seriously intoxicated Aboriginal woman who died in a holding cell.
Dr John Vine has told an inquest into Rebecca Maher's July 2016 death officers should have regularly entered the mother of four's cell at Maitland Police Station to check her welfare.
"She didn't move at all from the moment she lay down," Dr Vine told the coroner in Newcastle on Thursday. "That tells me she was unconscious almost immediately.
"If she doesn't respond or responds inadequately, then there's a big concern."
Acting Sergeant Gregory Hosie, who was station custody manager the morning Ms Maher died, told investigators he checked her condition seven times between 1.39am and 5.17am but did not enter her cell.
He watched her on CCTV footage in his office or peered into her cell from outside.
An autopsy revealed Ms Maher died from mixed drug toxicity after taking a combination of methadone and benzodiazepines leading to respiratory failure. She had not been drinking.
Acting state coroner Teresa O'Sullivan is investigating the circumstances surrounding her death after she was detained for being intoxicated.
Counsel assisting David Buchanan said the inquest would examine the custody management record created for Ms Maher and the way police assessed risks to her health.
A code of practice for police looking after intoxicated people in custody states they have to wake, speak to and assess their sobriety at least every 30 minutes or more frequently if necessary during the first two or three hours.
"Where you cannot rouse a person or their level of intoxication or consciousness has not changed or is of concern, get urgent medical help," it says. "Do all assessments in person, not by video."
Ms Maher was detained after she was found stumbling towards oncoming traffic along Wollombi Road in Cessnock with her boyfriend after 1am.
The inquest was told she was not searched because officers feared contracting HIV or hepatitis C. A post-mortem showed she did not have either, Mr Buchanan said.
After being placed in the cell, Ms Maher went to the toilet but could not walk in a straight line. At one stage she was sitting on the mattress leaning forward but was unable to keep herself upright.
She eventually lay down and did not move again.
Mr Buchanan said Ms Maher was found unconscious at 5.51am and could not be revived. Two bottles of benzodiazepines were later found in the left leg of her pants.
The inquest continues.