The death of an Aboriginal woman in custody in 2016 could have been prevented if police had called an ambulance or conducted more thorough searches while she was in custody, the state’s coroner has found.

Rebecca Maher, 36, was found dead inside a police cell at the Maitland police station in the NSW Hunter region just before 6am on 19 July 2016, about five hours after being taken into protective custody because she appeared intoxicated and had wandered into oncoming traffic.

The inquest had previously heard that when Maher was taken into custody she was stumbling, had slurred speech and could not sit upright on the bench in the observation cell. It also heard that police initially had concerns about her health, specifically her breathing.

On Friday, the acting state coroner, Therese O’Sullivan, handed down her findings into the death, saying given the level of Maher’s intoxication the police’s failure to call an ambulance was in breach of policy and that she “would have survived” if they had.

“Police should have concluded at that early stage that Rebecca was severely intoxicated,” she said.

If an ambulance had been called, she said “expert evidence suggests that Rebecca would have survived”.

She said the level of her intoxication meant Maher “should not have been kept in police detention and should have instead taken immediately to hospital”.

“There seemed to be a consensus among various officers that the power to detain an intoxicated person was to be exercised to allow [the person] to sleep off,” she said.

“I am troubled by this attitude.”

After Maher was detained in Cessnock she was placed in the cell at 1.24am and ordered 10 minutes later to lie down, because she was sitting slumped on the mattress and looked likely to fall over.

A custody officer walked to the door of the cell seven times between then and discovering her death and looked at her through the perspex wall, but did not enter the cell or try to shake her awake, despite earlier noting problems with her breathing.

When the officer did enter her cell at 5.54am, Maher was unresponsive and surrounded by vomit. She was declared dead just over 10 minutes later after police and paramedics were unable to revive her.

Maher – who had a long history of drug addiction – was found to have died from mixed drug toxicity, with fatal levels of the prescription benzodiazepine Alprazolam in her system, as well as methadone which she had been using to deal with heroin addiction.

After her death two pill bottles containing 29 Alprazolam or Xanax tablets were found in the left leg of her pants.

O’Sullivan found police had failed to conduct adequate searches on Maher because of a “misguided” fear of contracting an infectious disease, and had not conducted adequate checks on her while she was in the prison cell.

She said it was “likely” that at least one of the pill bottles were inside Maher’s pants leg at the time she entered the police cell, and that had a pat down search been conducted the bottle “may have been located” and “alerted [the officers] to the nature of her intoxication”.

She found the search was not conducted because of a “misguided fear of contracting an infectious disease” after a dispatcher had incorrectly told officers Maher was HIV positive.

O’Sullivan said the checks conducted on Maher’s welfare during the night were “not consistent” with police requirements, and that if the officer on duty had performed his duty adequately “it is very likely” he would have found Maher unconscious earlier and called an ambulance.

The 36-year-old Wiradjuri woman is the only Aboriginal or Torres Strait Islander person to die in a NSW police cell since the state introduced the mandatory custody notification service (CNS) in 2000.

Under the terms of the CNS, police must notify the Aboriginal Legal Service when an Aboriginal or Torres Strait Islander person is is in custody for an offence, but not for a person detained for intoxication.

On Friday, O’Sullivan recommended the NSW attorney general consider amending the law to extend the CNS to intoxicated persons, and that the commonwealth minister consider expanding the funding of the program.

She also recommended further training for police officers about infectious diseases, improved reporting for custody managers checking on people detained for intoxication and to be required to record efforts to identify and locate a “responsible person”.