Ambulances are being ramped on the fourth floor of a car park at Flinders Medical Centre, in Adelaide's south, in what has been described as a "desperate measure" at the hospital.
The South Australian Salaried Medical Officers Association's chief industrial officer Bernadette Mulholland said she became aware of the issue recently, but had been told by staff that level four had been used for ramped ambulances for the past six-to-12 months.
"What it demonstrated to us is the depth of the challenge facing our hospital sector," she told ABC Radio Adelaide's Stacey Lee and Nikolai Beilharz.
Ms Mulholland said the space was "quite close to the emergency department" and had dedicated ambulance-only access.
But she said difficulties arose in triaging patients when staff had competing, high priorities such as needing to take patients off the ramp to allow ambulances to go to their next job.
"If you're waiting in the emergency department waiting room and you've got a higher triage, and you need to be seen more quickly, the issue becomes, for the doctor and the nurse, 'whose life is more important here?'" she said.
Opposition leader David Speirs said he had been sent a photo showing 10 ambulances ramped on level four.
"Patients have approached us who have seen medical interventions occurring in that car park as patient health deteriorates," he said.
Mr Speirs said while the car park was "not that far away" from the ED, he was concerned the distance would "add to the complexity of patient care".
"It's clearly a concern if a medical situation deteriorates quickly, as can happen when you're in an ambulance, that you might not be able to get into the ED quick enough," he said.
Health Minister Chris Picton said he had heard of ambulances being ramped on the fourth floor of the Flinders Medical Centre car park "at least a year ago".
He said the government was building beds "as fast as we can" to address ramping.
"An additional 26 beds at Flinders Medical Centre have been progressively opening this week, and by the end of the week will be fully opened," he said.
Mr Speirs said using the fourth floor of the nearby car park was a "diversionary tactic to hide exactly how many ambulances are ramping and hide the visuals of that from the South Australian public".
But SA Health chief executive officer Robyn Lawrence said ramping hours were "made public on a daily basis".
"It's absolutely not about hiding it, and we're being very transparent on those figures," she said.
"It's about ensuring safety for all those concerned."
While she was unsure of the ramping location at Flinders, Ms Lawrence said sites were chosen to provide a "safe place for ambulances" that does not obstruct traffic.
"The location is designed to provide as much support to the ambulance officers as well as to the staff in the hospital," she said.
Opposition health spokeswoman Ashton Hurn said ramping was "so bad that they are forced into these desperate measures".
Ms Hurn said emergency departments in metropolitan Adelaide had operated at Code White, the highest capacity rating, twice in the past five days.
"That means there is not one single bed available in emergency departments across any single hospital," she said.
