Monash Health's emergency departments were thrown into chaos over the weekend after its electronic patient management system went offline throughout Friday and Saturday.
Hospital staff were forced to resort to manual paper lists to keep tabs on who had entered the department and for what ailment, with some patients forced to wait hours to be treated.
Monash Health implemented the "Symphony" electronic patient administration system across its three emergency departments - Monash Medical Centre Clayton, Dandenong Hospital, and Casey Hospital - during 2008-09.
Symphony is a product made by healthcare systems vendor Emis Health.
The system handled 206,602 patients passing through the three emergency departments in the year ended June 30 2015.
Generally the vast majority of those who present to the emergency department are dealt with in under four hours, according to Monash Health's most recent annual report. But over the weekend patients reported being left waiting for as much as 12 hours.
The Friday afternoon downtime meant emergency department staff were left to rely on paper-based lists of those waiting for treatment.
One affected patient at the Monash Clayton centre told iTnews the system problems caused such chaos that staff at one point lost track of which patients were waiting and for what treatment.
Update 3:15pm: Monash denied the Symphony system had crashed, instead saying it had initiated a "planned upgrade" on Thursday than ran for six hours.
It said the paper-based administration had been a deliberate backup measure.
"Business continuity plans were in place. Some minor issues have been encountered – with no impact on patient safety," a spokesperson said.
"All patients were safe."