The Supreme Court is continuing to hear legal argument over the validity of an investigation into the suspended head of the Royal Hobart Hospital.

Michael Pervan says he was denied natural justice when he was stood down as the hospital CEO six months ago, pending an investigation into staff complaints against him.

Mr Pervan went to the Supreme Court to challenge the validity of the inquiry and the conduct of the Health Department Secretary, David Roberts.

Justice David Porter last week ruled the application was successful, but only on the grounds that the scope of the investigation had been improperly expanded.

Yesterday, Mr Pervan’s lawyer Duncan Kerr argued the investigator had overstepped the boundaries and taken on the role of a prosecutor, instead of investigating the allegations against his client.