A defence psychiatrist has told an Israeli court that former Melbourne school principal Malka Leifer is unfit to face trial in Australia on charges of child sex abuse and rape.

But the integrity of psychiatrist Dr Brian Trappler to give evidence in court has been questioned, based on public statements he made in 2017.

As reported by The Australian Jewish News, Dr Trappler previously proclaimed

Leifer's innocence, writing on Facebook; "she never committed the crimes she was accused of."

As petitions were being delivered to force the Israeli government to follow up on

Leifer's alleged crimes and have her extradited to Australia, Dr Trappler declared the women calling for her to face trial were not 'frum,' or devout Jews.

He called the women, particularly those allegedly abused by the former principal at the ultra-orthodox Adass Israel School in Melbourne, a 'lynch mob.'

He further stated the Jewish women were committing a crime by reporting to

secular authorities.

After Wednesday's hearing, Manny Waks, CEO of Kol V'oz, an organisation preventing sexual abuse in the Jewish community, said Dr Trappler had no credibility as a witness.

"Today's hearing should have lasted no more than a few minutes.

"The prosecution should have presented the judge with Dr Trappler's previous absurd public statements regarding this case and the judge should have dismissed Dr Trappler as a witness," Waks told AAP.

Melbourne sisters Dassi Erlich and Nicole Meyer who were allegedly abused by

Leifer, travelled to Israel specifically to attend the closed court, now in it's 48th

hearing.

A public protest was held outside court to show support for the sisters.

The large crowd of supporters held signs reading "you're not alone," referring to

Leifer's victims, and chanted "we want justice."

Dassi Erlich thanked everyone for showing up and supporting them.

"Thank you for letting us know we are not alone, we feel your support, it is because of your support that we can continuing doing this ... continue fighting for justice and ensure this abuser is not on the streets anymore," Erlich told the crowd.

The sisters from Melbourne have been fighting for Leifer's extradition since she fled Australia in 2008.