Two South Australian hospitals are being investigated for concerning workload practices, including poor governance structure for medical interns.

Royal Adelaide Hospital and Queen Elizabeth Hospital both failed to obtain proper accreditation in their most recent visit from relevant accreditation bodies, being given a year to rectify these issues.

The SA Salaried Medical Officers Association said trainee doctors were the most vulnerable staff in hospitals, with the stripping of accreditation for hospitals to host TMOs being a worst-case scenario for the SASMOA.