Malka Leifer, 56, is facing 29 charges over the alleged sexual abuse of Melbourne sisters Nicole Meyer, Dassi Erlich and Elly Sapper when she was head of religion and principal at the Adass Israel School in the city's eastern suburbs.
Leifer, a mother of eight, has pleaded not guilty and is facing trial in the Victorian County Court.
The court is expected to be closed on Thursday when the first of the women begins their evidence.
It's believed to be the first time any of the women will be in the same room as Leifer in 15 years.
Prosecutor Justin Lewis opened the case against Leifer in front of a jury of 15 on Wednesday, alleging Leifer had a tendency to act in the way alleged.
"It is said she has a tendency to have a sexual interest in girls when they were teenage students at the school and when those same girls were student teachers … to take advantage of their vulnerability, their ignorance in sexual matters and her position in the school," he said.
She's accused of raping all three women, now in their 30s. Other charges include indecent assault and sexual penetration of a child aged 16 or 17.
After allegedly raping Ms Meyer shortly before her wedding, Mr Lewis said Leifer told her "this will help you for your wedding night".
She's also accused of sexually abusing Ms Meyer and Ms Erlich when the trio shared a room on a school camp.
Leifer also allegedly told the youngest sister, Ms Sapper, after abusing her on multiple occasions that "this is good for you".
Leifer's barrister Ian Hill KC said the defence position was that the allegations are "erroneous, imagined and/or fabricated".
"Mrs Leifer denies all of the criminal conduct alleged by each of the complainants," he said.
"You will hear that in 2008 she said to a fellow teacher … that she had done nothing wrong."
He said jurors were expected to hear there was a positive, glowing and appropriate relationship between Leifer and the sisters.
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