Nineteen South Australian prison guards are attempting to have a coroner removed from investigating the death in custody of an Indigenous man, after seven guards lost a bid to avoid giving evidence at the inquest.

Wayne Fella Morrison died, while in the custody of the guards, after being pulled blue and unconscious from a transport van where he was forcefully placed face-down on the back seat in 2016.

The prison guards had argued that they should have the right to silence, when being asked to give evidence which could leave them open to civil or disciplinary action.