A child protection worker has been awarded compensation after she was forced to shelter in a bathroom while a group of teenagers threatened to kill her and a young girl in her care.

The woman, who the ABC has chosen not to name, said her August 2018 ordeal began when three residents of a home for young people in state care became aggressive towards a girl in the house.

The woman locked herself and the girl inside the office while the teenagers, who had been joined by a fourth person, banged on the door and windows.

As the situation escalated, the pair fled to the bathroom because it had a solid door with no windowpane, and the window was not big enough to climb through.

In evidence before the South Australian Employment Tribunal, the woman said she could hear the group screaming that they would kill her and the girl.

She recalled the group continued to bang on the window and jump on the roof in an effort to get inside.

"[She] says that she was scared for her safety but had to try to remain composed so as not to stress further the young girl whom she was protecting," Magistrate Stuart Cole said in a judgement published this week.

After two hours locked inside, police arrived and the pair was able to make a safe exit.

Less than two weeks after the incident, the woman and another residential care worker decided to take the four teenagers involved to the beach.

In her evidence, the woman said she "felt like the car was closing in on her" during the journey, and that she was shaking and her heart was pounding.

She vomited at a petrol station, felt hot and sweaty and told her colleague she could not continue the shift.

"She remained anxious and unable to stop shaking and sweating, even after she arrived home with the assistance of her partner," the judgement said.

The woman visited her doctor and has not been able to return to work since that shift because of overwhelming work-related anxiety.

Tribunal hears of 'regular violent incidents'

The tribunal heard the 2018 incident was the last in a series of traumatic events the woman had been involved in since she was employed by the Department for Child Protection in 2013.

Her supervisor gave evidence that the last house she was assigned to was home to "more complex" residents, who required more care and skill to manage.

"Each of the residents had behavioural and/or mental health problems, and each had come from difficult family backgrounds deficient in proper and adequate modelling of behaviour," the judgement said.

The woman was assessed by two experts who agreed she had a psychiatric condition, but the department argued it could not be proved that her condition was a result of her work.

Instead, it argued that the woman's psychiatric injury was caused by events in her personal life.

But Magistrate Cole ruled the primary cause was the 2018 incident, adding that "personal stressors" were not important or influential.

He accepted the woman's claim for compensation, but an amount has not yet been decided on.