· In short: SA Health has cancelled elective surgeries for 48 hours due to capacity issues across the health system and the difficulty of discharging patients over Easter.

· The government has defended the timing of the announcement, two days after the Dunstan by-election.

· What's next? The doctors' union is calling for urgent solutions to ease the pressure at several hospitals in metropolitan Adelaide, in particular Flinders Medical Centre.

The head of South Australia's health department has defended a decision to postpone elective surgeries days out from the Easter long weekend, which will pause some medical procedures for almost a week to free up space in public hospitals.

Department for Health and Wellbeing chief executive Robyn Lawrence said Tuesday's decision to pause elective surgeries for 48 hours in SA's public hospitals would create additional beds before Easter.

"All of our beds are full, we have every single bed in our system open and we have over 500 patients who have been in our hospitals for over 21 days," Dr Lawrence said.

"Over Easter [it's] difficult to discharge patients compared to a usual day because many of the home alternatives that people would go to, such as residential aged care and home care pathways, are not available.

"Therefore we felt there was an urgent need to create capacity to enable our patients to flow through our emergency departments."

Dr Lawrence said local health networks made daily decisions based on each hospital's capacity. 

"What we've seen over the last few days, and in fact the last couple of weeks, is sustained pressure," she said.

She said she apologised to patients who had their elective surgeries delayed.

So far 33 patients have had their surgery put on hold, and anticipated "resuming normal activities post Easter".

Shadow Health Minister Ashton Hurn said there are nearly 19,000 people in South Australia waiting for elective surgery.

"This decision is obviously going to leave so many people put out, essentially they've had the rug pulled out from under them and we need to see these elective surgeries rescheduled as soon as possible,' she said.

Premier unaware before by-election

The opposition has also criticised the timing of the announcement, which came days after the Dunstan by-election vote that saw Labor gain the seat from the Liberal Party.

"For this abrupt cancellation to occur just two days after the Dunstan by-election, I think, is a big coincidence," said Ms Hurn.

Premier Peter Malinauskas defended the timing of the announcement, and said he was first notified of the elective surgery ban on Tuesday.

"We've got a bit over 150 new beds coming online throughout the second half of this year and then another 130 beds coming online next year and then progressively continues from there to get a lot more beds," he told ABC Radio Adelaide.

Dr Lawrence said she did not discuss postponing non-urgent surgeries with her team or the government last week.

"The situation yesterday was assessed by myself and by my CEOs and we had a range of discussions about that during the day," Dr Lawrence said.

"With respect with anything to do with a by-election, that's a political issue. I'm here to serve the people of South Australia."

"We took the decision based on the healthcare system and the needs of our acute patients," she said.

Weeks of sustained pressure

The South Australian Salaried Medical Officers Association (SASMOA) said some elective surgeries had already been cancelled at the Flinders Medical Centre (FMC) in the past two weeks when it was operating under an internal emergency code.

SASMOA chief officer Bernadette Mulholland said she was told by Southern Adelaide Local Health Network (SALHN), which includes the FMC, that the high demand in past weeks was caused by heat-related cases and that "it'd hope that it would be resolved shortly".

Ms Mulholland said the pressure on South Australian public hospitals in the last few weeks had been "quite extraordinary".

"Within FMC we had seen there were 37 patients who had been waiting for a bed – that had probably been the highest I'd seen a couple of weeks ago," she said.

Hunt for solutions

Ambulance Employees Association general secretary Leah Watkins told ABC Radio Adelaide an option to postpone elective surgeries was being considered when FMC was overcapacity.

"It was reported that ramping hours being lost per day over this two-week period have reached record levels and that was having a significant impact on ambulance response times for emergency cases," Ms Watkins said.

"These ramping figures are across the metropolitan areas, it's not just within the SALHN catchment."

"Our concern was that something needs to be done, there needs to be a tangible step change to be able to free up capacity in a significant way for this immediate issue where we are heading into a long weekend and we know there's going to be a decreased number of hospital discharges over that time," Ms Watkins said.

"We always see this, this is a regular pattern when hospitals fill up over that period."

Orthopedic surgeon Michael Selby, who has worked in hospitals for over two decades, said delaying elective surgeries "kicks the can down the road".

"When these medical events happen, we do try to take patients on to our elective list into emergency surgery on those lists but you can't always fill them," Dr Selby said.

"Often we have operating theatres, surgeons, nurses, anaesthetists sitting idle while the wards are full with patients."