Australia's most senior rabbi, Meir Shlomo Kluwgant, has resigned as president of the Organisation of Rabbis of Australasia (ORA) after a damning stint in the witness box at the royal commission into child sexual abuse.

Rabbi Kluwgant gave evidence on Friday, and was forced to admit he had sent a text message to a newspaper editor calling the father of an abuse victim a "lunatic" who neglected his children.

The message referred to Zephaniah Waks, father of Yeshivah community whistleblower Manny Waks.

The admission was made after the Waks' family lawyer confronted Rabbi Kluwgant.

At first Rabbi Kluwgant said he could not recall sending the text, but then admitted he sent it to the editor of the Australian Jewish News, Zeddy Lawrence, on February 3.

Mr Waks' son Manny was molested by convicted paedophile David Cyprys.

Mr Waks told the commission he renounced the ultraorthodox Chabad movement after his family was persecuted for going public about the abuse.

'He is a lunatic on the fringe'

The text message from Rabbi Kluwgant to a newspaper editor read "Zephaniah Waks is killing us. Zephaniah is attacking Chabad. He is a lunatic on the fringe, guilty of neglecting his own children. Where was he when all this happened?"

When the message was first raised by the Waks' family lawyer, Rabbi Kluwgant had just said he did not approve of shifting the blame onto the parents of child abuse victims.

At first he said he could not recall sending a message to Mr Lawrence, but admitted it after the message was read out in its entirety.

Manny Waks immediately called for Rabbi Kluwgant's resignation and accused him of being involved in a "long going campaign of intimidation and harassment" of himself and his family.

"It's been very difficult to prove until now," Mr Waks said.

Mr Waks recently moved his family to Europe as a result of ongoing harassment and his parents have left Melbourne for Israel.

He responded to Rabbi Kluwgant's resignation as he was preparing to fly out of Sydney on Monday.

"Obviously his position as a leader within the community was untenable," Mr Waks wrote in a statement.

"My thoughts are with him and his family at this difficult time for them.

"Hopefully he will take the time to educate himself about this issue ... hopefully this will assist in the healing for victims/survivors and their families, as well as the broader community."

Rabbi apologises to abuse victim

Mr Waks also said he had received an email of apology from Rabbi Kluwgant since Friday's hearing.

Victoria Police has also confirmed Rabbi Kluwgant no longer holds the post of police chaplain, a position he had held for six years.

His resignation followed the resignation of senior Sydney Rabbi Yosef Feldman, who gave controversial evidence at the royal commission the previous week.

Rabbi Feldman stood down as director of the Yeshivah College in Bondi, but remains a teacher.

He told the ABC he hoped to return to the position in the future.

Several senior members of Melbourne's Yeshivah community who were in positions of power when the scandal broke have also since resigned.

They included the principal of Melbourne's Yeshivah College from 1986 to 2007, Rabbi Abraham Glick, and former general manager Nechama Bendet.

Both issued apologies to victims at the Royal Commission, as did other senior Rabbis.

Figures from Australia's broader Jewish community have called for more resignations, and a watchdog to be set up, since details of Yeshivah's response to child abuse allegations were aired at the commission.