The union representing South Australian paramedics has launched legal action against SA Health and the SA Ambulance Service (SAAS) because of increased overtime and on call pressures.

Key points: The union said it was the most extreme measure it could take

The union said it was the most extreme measure it could take Patient Horst Birvé was ramped for three hours at Flinders Medical Centre last month

Patient Horst Birvé was ramped for three hours at Flinders Medical Centre last month The union and the State Government have six weeks to negotiate

Ambulance Employees Association president Phil Palmer told the ABC at one point yesterday 20 ambulances were ramped at two of Adelaide's public hospitals, with some crews waiting for three hours.

He said the court action was the most extreme measure the union had taken against the State Government.

"We've taken the ambulance service and the department … to the industrial court because the workload is so high, the demand is so great," he said.

"The data provided to us by [SAAS] shows a significant shortage throughout nearly half the day, every day.

"Our next step will be to take it to trial and we'll be seeking orders on the Government."

It is understood the union and SAAS met twice late last year before a hearing was held in the tribunal on Wednesday.

Both parties will now have six weeks to solve issues around meal breaks, the use of overtime and how to reduce pressure.

The ABC has launched an investigation into the state of South Australia's health system, with revelations on the union's court action the first in a series of exclusive reports to be published in the coming week.

Overtime and on call work needed to maintain resources

Mr Palmer said the ambulance service had an "unsustainable reliance" on overtime and on call work to maintain minimum resources and said "a life's going to be lost in this".

Phil Palmer said the court action was an "extreme measure". ( ABC: Claire Campbell )

He said, under figures provided by SAAS, $660,000 was being spent on paramedic overtime payments every fortnight.

"If overtime was withdrawn, the ambulance service would collapse in a day," he said.

"There's people coming in on their days off to help the ambulance service [keep] running.

"The current Government's continuing the practice of the former government, just doing nothing."

Family was not told where sick loved one was taken

Port Willunga resident Horst Birvé, 88, said he had experienced the pressure on the system firsthand, and was "ramped" twice in the past six months.

Last month, he spent three hours in the back of an ambulance before he could set foot in Flinders Medical Centre's (FMC) emergency department.

"Well you can crack a few jokes in that time, but after three hours it is getting serious," he said.

"Your patience is running very thin and you begin to wonder [if] there is something wrong in the system somewhere and nobody is taking any notice of it."

In the most recent incident, Mr Birvé waited in the back of the ambulance without any contact with his family.

His son Andrew Birvé became increasingly worried about where his father was as he had not been admitted to FMC and nobody could tell him which hospital he had been taken to.

"Of course, as anyone would do, I tried to find out where he was admitted," he said.

"The first thing I did was ring the Flinders Medical Centre about an hour after he left [in the ambulance] and they said 'no, no we've got no record of him being at the Flinders Medical Centre' and they recommended I call around the other hospitals.

"I was quite concerned … I think most people would be quite worried if they lost a patient after leaving home."

Horst Birvé has been ramped in an ambulance twice in six months. ( ABC: Claire Campbell )

He rang several other hospitals throughout Adelaide, none had any record of his father being admitted that day.

He called on the health system to become more transparent about who was waiting in an ambulance.

"This would be just one step towards improving, if we could get some information about our loved ones if they're ramped," Mr Birvé said.

"For a while I've been suspicious that the health system is decaying and that confirmed it to me.

"There's a lack of thought put into the processes and procedures."

When his father was eventually admitted to FMC, he said he had to wait another six hours before he was seen in the "curtain corridor".

His father questioned why patients with private health insurance could not be taken to private hospitals to help reduce overcrowding in public hospitals.

"I would prefer not to repeat it again and not many people would … you're not a patient, you're a number," he said.

"I am privately insured, I have an ambulance insurance, I couldn't insure any more but that doesn't help you.

"You begin to wonder why can't I go into the private hospital but nobody gives you any answer to that."

Government will continue discussions

Health Minister Stephen Wade said the union was entitled to stand up for its members in whatever forum it wanted to.

"We'll continue to work with the industrial bodies and with the employee representative bodies to work through these issues," he said.

"We share the same goal as the ambulance association — that is to eliminate ambulance ramping and deliver the best possible care to our patients.

"I'm having very productive discussions with all of the relevant employee associations, I speak to them regularly and I will continue to do so."

Mr Wade said reports that there was a shortage of ambulances in Adelaide yesterday were incorrect.

"It is wrong to say the SA Ambulance Service was not able to respond to emergencies," he said.

"Ambulance ramping is completely unacceptable, that's why we're opening beds."