Confidential medical records of at least 12 mental health patients were left in the courtyard of a regional West Australian hospital, parliament has heard.
Labor MP Peter Watson said the documents included names, reasons for admission and suicide risk assessment details, and were found by a visitor at Albany Hospital.
Mr Watson asked Health Minister John Day how such a significant breach of privacy could occur and was told the mistake appeared to have happened on May 29 during a shift handover.
"It is a very serious issue - there is no question about that," Mr Day said.
"We have asked for a full investigation and indeed a report will be provided to us as soon as that is completed.
"It would appear to be as a result of human error. Somebody has made a mistake. People do make mistakes.
"This is not an issue in any way caused by the government or the senior administration of the health system in Western Australia."
Mr Day told parliament he'd only learnt of the matter on Tuesday through a media query but accused Mr Watson of a "media stunt", saying the member for Albany had known about it since June 8 and should have immediately told the WA Country Health Service.