Prisoners are sharing methadone by regurgitating their prescribed doses and passing the drugs onto other inmates, a coronial inquest into a fatal overdose at a jail has been told.

Key points: Wyatt William Azaparti fatally overdosed on methadone at Port Augusta Prison in 2016

Wyatt William Azaparti fatally overdosed on methadone at Port Augusta Prison in 2016 An inquest into his death heard he likely accessed the drug from another inmate

An inquest into his death heard he likely accessed the drug from another inmate A safety policy to prevent such occurrences was earlier scrapped, an officer said

South Australian coroner Mark Johns is investigating the death of Wyatt William Azaparti who died from a methadone overdose at Port Augusta Prison in April, 2016.

The inquest heard at the time of his death Azaparti was not one of the eight inmates at the prison who was medically prescribed methadone.

It heard the 45-year-old likely accessed the drug through "diversion" — a method used by prisoners throughout the world — where a prisoner who is medically prescribed a drug regurgitates it and sells it to another inmate.

It was also told corrections officers were helping to facilitate the drug trade within prisons.

Detective Brevet Sergeant Jason Olsen gave evidence on the prescription drug trade. ( ABC News: Rebecca Opie )

In his evidence, Detective Brevet Sergeant Jason Olsen told the court that the prescription drug trade in South Australian prisons was a major concern for police and the Department of Correctional Services (DCS).

"It creates a trade, it creates a situation where prisoners are being stood over, where prisoners are incurring drug debts in prison," he said.

"Visitors and family are being pressured to commit offences to bring this drug into prison.

"DCS officers are committing criminal offences by bringing this stuff into prison."

The inquest heard in the months leading up to Azaparti's death, the DCS scrapped its policy requiring corrections officers to supervise prisoners after they took their prescribed dosage of methadone.

The safety measure was discontinued because it was "a drain on their resources".

"The previous procedure where prisoners were required to remain in the dosing area for a period of time required corrections officers to be present to observe and that was a drain on their resources, so management decided that process would stop," Mr Olsen said.

The inquest heard that after Azaparti's death the DCS started observing inmates for 10 minutes after they had taken their prescribed dosage of methadone.

Prisoner drank methadone from a 'coke bottle'

Methadone and the drug suboxone are commonly used to treat opioid dependence.

Methadone is used in the treatment of heroin addicts. ( ABC News )

The court heard health authorities in prisons interstate had started to move away from prescribing suboxone and back towards methadone.

Mr Olsen said if South Australia followed the trend there could be more fatal methadone overdoses.

However, he said suboxone was a bigger problem in prisons because it took longer to dissolve than methadone.

"Suboxone is creating enormous issues and criminal enterprises within prison," he said.

"Unless procedures are put in place … perhaps prisoners are isolated for half an hour or whatever is required — I think this will probably continue."

In her opening address, counsel assisting the coroner Naomi Kereru said Azaparti's cellmate told an investigating officer Azaparti was drinking methadone out of a coke bottle the day before he died.

However, Ms Kereru said that information was not passed on to the officers who searched the cell and the coke bottle was thrown out before it could be examined for evidence.

Azaparti was sentenced to six years in prison for a number of offences including serious criminal trespass, theft and assault, but shortly before his death he was granted permission to appeal against his convictions.

The inquest continues.