Former Socceroo Steve Herczeg suffered a "cruelly painful" death after an unknown person wrongly connected his urinary catheter to an oxygen supply, bursting his bladder, an inquest has found.
Coroner Mark Johns said in the "awful and macabre" circumstances of his death, the 72-year-old's body blew up "much like a balloon" before he died in Adelaide's Queen Elizabeth Hospital in September last year.
Mr Johns said he was reluctant to find that Mr Herczeg, who was confused during his time in hospital, connected the wrong tubes himself because of the complexity of the task and the number of manoeuvres involved.
But he said could not exclude such a possibility and, given it was was "abhorrent to think that a member of the nursing staff would do it deliberately", ruled that the tubing was interfered with by an unknown person.
Herczeg had been admitted to hospital to treat a urinary tract infection, something the inquest was told was uncomplicated.
A police report into his death concluded he probably connected the wrong tubing himself.
But evidence showed that medical staff also made errors in the lead-up to his death.
One nurse put him on oxygen despite a doctor advising it wasn't needed at the time and another failed to check his catheter before handing him over to a colleague.
Mr Johns said it was clear that if Mr Herczeg had not been placed on oxygen his death would have been prevented and criticised the care he received.
"It is plain to me that the nursing staff responsible for his care on Ward South 1, did not provide an adequate level of care and supervision to Mr Herczeg," the coroner said.
"Had they done so, this tragic event would not have occurred."
Mr Herczeg was the first South Australian to play for Australia in a FIFA World Cup qualifying match.
He took the field in 1965, playing in a match against North Korea in Cambodia.