An Aboriginal mother who died from "mixed drug toxicity" while in a Maitland police station cell might have survived had she been adequately assessed, an inquest has heard.
Acting state coroner Teresa O'Sullivan is investigating the circumstances surrounding the death of Rebecca Maher in July 2016 after she was detained by police - who wrongly believed she had HIV - for being intoxicated.
Counsel assisting the coroner David Buchanan told the court in Newcastle an autopsy had revealed toxic levels of methadone and benzodiazepines in the mother of four's system leading to respiratory failure.
Mr Buchanan on Monday said medical evidence would be given that the Wiradjuri woman could have survived if she'd been adequately assessed by police and an ambulance called.
Police had detained Ms Maher after she was found stumbling along Wollombi Road in Cessnock into oncoming traffic with her boyfriend after 1am.
Sergeant Nathan Brooks told investigators police detained her because there were doubts she lived at the address she'd given.
Police also assumed no responsible person would be there to look after her.
Mr Buchanan said Ms Maher was not searched before being placed in the cell because officers feared contracting HIV or hepatitis C.
Ms Maher was well known to police but the wrong information had been recorded about her medical background stating she had HIV or hepatitis C.
After eventually lying down in the cell on a mattress, Ms Maher did not move again.
The police station's custody manager, Acting Sergeant Gregory Hosie, noted she was: "Sleeping in cell. Nil issues at this stage. Being monitored closely due to intoxicated state."
Mr Buchanan said Sgt Hosie checked on Ms Maher seven times between 1.39am and 5.17am but did not actually go into her cell.
Sgt Hosie would look at the CCTV footage or peer into the cell from outside the door.
Mr Buchanan said no officer attempted to wake Ms Maher or check her breathing.
Sgt Hosie at 5.51am knocked on the cell door a number of times but there was no response.
A minute later he entered the cell but did not touch Ms Maher. He then left the cell and returned another minute later wearing gloves.
Mr Buchanan said Ms Maher's face and hands were blue when Sgt Hosie shook her but she did not respond. He then ran out of the cell and returned with a defibrillator but did not know how to use it.
Police called triple zero at 5.54am but paramedics could resuscitate her.
Mr Buchanan said police later found two bottles of benzodiazepines in the left leg of Ms Maher's pants.
He said it was a matter of concern police did not inform Ms Maher's mother, Debbie Small, about her daughter's death until 12.20pm and the news was not conveyed by a commissioned officer with the rank of inspector or higher which was the usual practice.
The inquest continues.