A nurse has been stabbed in the neck after leaving work at a South Australian hospital, sparking concern and prompting a warning that patient aggression is "escalating".

Key points: Police are searching for a man suspected of stabbing a nurse outside the Lyell McEwin Hospital

Police are searching for a man suspected of stabbing a nurse outside the Lyell McEwin Hospital A witness said he heard a man "yelling obscenities" at a woman outside the hospital

A witness said he heard a man "yelling obscenities" at a woman outside the hospital Nurses' representatives have been lobbying the Health Department for a "10-point plan" to improve security

Police were called to the Lyell McEwin Hospital, in Elizabeth Vale in Adelaide's north, after a woman was stabbed in the neck about 6:30pm on Monday.

In a statement, SA police said a man asked the nurse for a cigarette as she was leaving work before he stabbed her with a "sharp object".

He then fled from the scene.

But police have today arrested a 28-year-old man of no fixed address who was located in Murray Bridge.

He will face charges of aggravated intentionally causing harm and aggravated endanger life and is expected to be refused bail to appear in the Murray Bridge Magistrates Court tomorrow.

The victim was treated at the Lyell McEwin Hospital for non-life-threatening injuries.

Australian Nursing and Midwifery Federation state secretary Elizabeth Dabars said security was an issue at the Lyell McEwin Hospital, and at other hospitals across "the system".

"We have held long concerns and have been advocating for action on violence and aggression for a long time now, both within the hospital system and for those getting to and from the hospitals," she said.

She said she had been lobbying the Health Department for a "10-point plan" that would boost security, highlight risks and change workplace design to improve safety.

"It's about training and education of staff," she said.

Ms Dabars said it was also about "improving the situation for our really dedicated and hard-working nurses, midwifes and other healthcare professionals".

"[They] quite frankly deserve to go to work and feel safe — and actually be safe — because the reality is that violence and aggression is getting all too common," she said.

"It is escalating."

Nursing and Midwifery Federation state secretary Elizabeth Dabars outside the RAH in October 2018. ( ABC News: Leah Maclennan )

In a statement, an SA Health spokeswoman said the victim was in a stable condition but would be transferred to the Royal Adelaide Hospital for further tests.

"The nurse was on her break, and approached by an unknown man near Haydown Road when the incident occurred," she said.

"The nurse is currently well-cared for and supported. The safety of our staff and patients is always our priority."

A witness — who did not want to be named — told ABC Radio Adelaide that he did not see the actual stabbing but heard a commotion not far from him.

"I saw someone follow me from the inside of the building out ... approaching a lady, and then I heard him yelling obscenities," he said.

"I saw him leaning over towards her, him yelling obscenities, and that's pretty much it.

He said by the time he looked back at the altercation, the man had fled and the victim had rushed back into the hospital.

In 2015, staff at the Women's and Children's Hospital in North Adelaide raised safety concerns because of parking pressures created by Adelaide Oval.

Adelaide City Council then created 128 new permit parking spaces for hospital staff and allowed exemptions from event parking restrictions tied to events at the oval.

Anyone with information about the Lyell McEwin Hospital assault is urged to call Crime Stoppers on 1800 333 000.