A Tasmanian dementia patient found with maggot-infested leg wounds only received sub-par care for a 24-hour window.
That's the finding of a wide-ranging independent review into Hobart's Roy Fagan Centre, where the grisly discovery was made during a Christmas Day visit.
The 78-year-old man's wife and adult daughter visited him on December 25 last year, two months after he was admitted to the specialist facility for people with psychiatric illnesses or cognitive impairment.
"Their time together should have been a time of pleasure, to exchange gifts and be accompanied by good memories," said the Office of the Chief Psychiatrist report, released on Tuesday.
"Unfortunately, when the family went into his bedroom to change the clothes of their loved one, they discovered fly larvae within one of his socks."
Distressed, the family took photos and a short video of his condition before he was moved to Royal Hobart Hospital.
The fallout from the incident triggered a broad independent review into the Roy Fagan Centre and Tasmania's network for Older Persons Mental Health Services (OPMHS).
It found the standard of care provided to the patient - known as "Mr A" - in the 24 hours before Christmas Day "fell well below an acceptable standard", despite previously being satisfactory.
"Greater efforts should have been made, at that time, to properly address Mr A's care needs and provide him with greater dignity," the report said.
Mental Health and Wellbeing Minister Jeremy Rockliff said he had called the family to again formally apologise over the "traumatic" and "deeply distressing" incident.
Chief Psychiatrist Aaron Groves said it was "highly conceivable" the maggots formed just 24 hours before being discovered by his family.
"I was able to get the expert services of the Victorian forensic institute and they were able to inform me that, in fact, in Tasmania we have a species of fly that actually lays both eggs and live larvae," Dr Groves told reporters on Tuesday.
"In other words, maggots can be laid by the fly and, in fact, its endemic in southern Tasmania."
No single staff member was at fault for the man's condition, the report said, instead blaming the failure on a culmination of factors including insufficient resourcing, rostering practices and worker unavailability.
The report said the Lenah Valley facility was both out of date and inadequate for some patients, and had no contemporary model of care.
"There is an insufficient number and type of nursing staff for the variety and complexity of patient need," it said.
Overall, it noted there had been "inadequate attention" paid to OPMHS in Tasmania and a lack of investment in the program despite the expected rise in the state's ageing population.
The Tasmanian government has accepted all six recommendations of the report including that OPMHS be made a statewide program and that the Roy Fagan Centre develop a model of care based on resourcing levels needed for the next decade.
"The Roy Fagan Centre workforce is well placed to embrace change and improvement," Mr Rockliff said.
"Clearly we can do better. We owe it to Tasmanians."
He is confident the incident will never be repeated.