Helping to ease the trauma of giving evidence to a courtroom, three-year-old female support dog Coop sits with sexual assault victims as they face the ordeal of having to recount an attack in detail.

Coop does not go inside the courtroom. Often victims sit in another room and give their evidence to the court via a video link.

Calm and silent, Coop sits alongside those victims, out of the view of the camera.

Trained from when she was eight weeks old, Coop has previously worked with agencies who support victims of sexual assault and family violence, and has sat in case conferences between victims and lawyers.

On those occasions she often sits in a victim's lap and has been known to lick away tears.

"She's enabling a person to tell their story in a less stressful, less anxious environment," says John Cain, head of Victoria's Public Prosecutions legal practice, "and anything that helps a witness tell their story more clearly and quickly has got to be good for the system".

"Most people don't encounter the criminal justice system in their life, but for complainants of sexual assault that one time can be very traumatic.

"At the extreme level people are upset, crying, very anxious, fidgety; they can't sit in the one place for long and they are overwhelmed by the whole process."

How Coop eases a complainant's distress depends on what the witness needs.

In the room, Coop will lie or sit at the witness's feet, offer them a paw to hold or even put her head in their lap.

Some people draw comfort from simply holding her lead, others prefer to pat her, or let her lick their hands.

One woman, who can only be identified as Penelope for legal reasons, has given evidence twice in court.

The first time she was so overwhelmed she was unable to focus on the questions. But the second time, she had Coop by her side.

"The moment Coop came running in she went to me and it felt more special than anyone else there because Coop was there just for me," she says.

Penelope said she was fine for the first 10 minutes of questioning, but when anxiety struck she began patting Coop, which relaxed her and kept her focused.

"My attention was on Coop and it pulled me out of the situation so I was able to focus on the facts and not the emotions."

Judges and magistrates must approve of the dog's presence, but juries are none the wiser, because the Labrador is not allowed to be seen on the screen, to ensure impartiality.

Her role began when public prosecution's staffer and dog lover, Julie Morrison, reached out to Coop's trainer, Tessa Stow.

The two women knew dogs had been successful in providing support in court settings across the United States, and thought the initiative was worth trying in Victoria.

"She [Coop] gives a sense of kindness, normalcy in a place which is repeating a trauma most clients do not want to relive," Ms Stow says.

"Our justice system runs on stressing victims, whether intentional or not."

On the day Coop is photographed by The Age she bounds into a foyer to greet a complainant quietly waiting to give evidence, and an instant rapport was struck.

Coop's presence often means complainants need fewer breaks when giving evidence - although she also needs a drink and run outside - and it is likely she and other trauma support dogs will play a full-time role within the legal system.

"Based on the results so far, it is unarguable," Mr Cain says.