A coronial inquest into the death of an Aboriginal man in custody has heard prison guards should not be required to give evidence because of the risk of self-incrimination.

Key points: The coronial inquest into the death of Wayne Fella Morrison is continuing

The coronial inquest into the death of Wayne Fella Morrison is continuing Lawyers for the guards say their input might expose them to criminal prosecution

Lawyers for the guards say their input might expose them to criminal prosecution The family of Mr Morrison says the role of an inquest is to "find out what happened"

Wayne Fella Morrison, 29, died in September 2016, three days after being restrained by a group of prison officers and placed facedown in a van at Yatala Labour Prison because he had assaulted staff.

The officers inside the van have been summonsed to give evidence but lawyers representing all seven prison guards have requested a blanket release for their clients citing the self-incrimination privilege under the Coroner's Act.

Wayne Fella Morrison died in hospital after being restrained by a group of prison officers. ( Facebook: Latoya Rule )

David Edwardson QC told the inquest no meaningful questions could be answered without fear of the prison guards incriminating themselves.

"The van witnesses should not be required to attend at all," he said.

"It's difficult to see how any question that could be asked could not infringe the right against self-incrimination.

"Having regard to the seriousness of the position, or potential seriousness of the position of each and every officer that was involved in the restraint of the prisoner… ultimately means that those officers potentially could have been exposed to a criminal prosecution or a criminal charge."

Mr Edwardson said the specific topics which would "absolutely" evoke his client's right not to answer included past training and education, presence, knowledge, state of mind, activity and inactivity.

Witnesses should give evidence, family lawyer says

Claire O'Connor SC, representing Mr Morrison's family, argued blanket privilege should not be granted.

Claire O'Connor SC leaves court after arguing the prison guards should be compelled to give evidence. ( ABC News: Claire Campbell )

She told the inquest there were at least three prison guards inside the van, including the driver and a guard in the passenger seat, who "could not possibly be suspects in relation to any crime".

"It's not a crime to fail to prevent a crime and it's not a crime for anyone who was in a position observing a crime to tell someone about that crime," she said.

"We do say that the witnesses should be required to give evidence, on oath, and be required to answer questions that will not tend to incriminate them.

"One role of an inquest is to find out what happened."

Counsel assisting the coroner Anthony Crocker told the inquest "the court can clearly inquire into those matters".

"We do have missing material, things we would normally expect to have," he said.

"The absence of it might be entirely appropriately explained in due course, but to suggest that you can't inquire into it is, with respect, a proposition that runs entirely counter to everything that is said about the nature of [a] coronial investigation."

Deputy State Coroner Jayne Basheer is expected to make a ruling next week.