Elly Sapper began her evidence behind closed doors in Melbourne Magistrates Court on Friday, after the court heard evidence from her sisters Dassi Erlich and Nicole Meyer.

Her testimony is expected to continue on Monday, after the previously predicted five-day hearing was extended into next week.

Leifer, 55, is facing 74 charges of child sexual abuse involving the sisters during her time at Melbourne's Adass Israel School between 2004 and 2008.

Most of the evidence so far has been heard in closed court, with only lawyers, Magistrate Johanna Metcalf and Leifer present by videolink.

But it opened briefly on Thursday for former school cleaner Mario Toledo to confirm he saw Leifer at the school on various Sundays in the company one, two or three girls.

Through a Spanish interpreter he said he never heard conversations between any of them though.

"I never paid any attention," he said.

He is one of nine witnesses expected to give evidence in the committal hearing.

Court is expected to open again on Monday afternoon to hear from former Adass Israel School counsellor Chana Rabinowitz, who will give evidence from Israel.

Clinical psychologist Dr Vicki Gordon and former Adass Israel School teachers Esther Spiegelmen and Sharon Bromberg are also on the witness list.

Witnesses and Leifer, who is currently at Melbourne's women's prison, the Dame Phyllis Frost Centre, are all appearing by video link.

Australian Associated Press