High Court Chief Justice Susan Kiefel said in a statement on Monday the court was "ashamed that this could have happened at the High Court of Australia".

An investigation report by former inspector-general of intelligence and security Dr Vivienne Thom has been provided to the six complainants and Justice Heydon.

The court was advised in 2019 of allegations of sexual harassment against the former judge.

"The investigation found that six former court staff members who were judges' associates were harassed by the former justice," Justice Kiefel said.

"The findings are of extreme concern to me, my fellow justices, our chief executive and the staff of the court.

She said a sincere apology had been given to the six women, who had made difficult decisions to come forward with their complaints.

Until now the court has not spoken publicly about the investigation.

A number of women requested confidentiality.

"The court now confirms that the subject of the investigation was the Honourable Dyson Heydon AC QC," Justice Kiefel said.

"We ask that the media respect the privacy of the complainants."

Mr Heydon told the Sydney Morning Herald via his lawyers Speed and Stacey: "Any allegation of predatory behaviour or breaches of the law is categorically denied by our client."

"Our client says that if any conduct of his has caused offence, that result was inadvertent and unintended and he apologises for any offence caused."

Among the allegations reported by the Herald, Mr Heydon inappropriately touched women at functions and took young associates back to his chambers and his accommodation where he harassed them.

Maurice Blackburn principal lawyer Josh Bornstein, who notified the court of the complaints in March last year, said the investigation had unveiled a "pattern of predatory behaviour" and highlighted a gap in both addressing judicial misconduct and protecting employees from misconduct.

Mr Bornstein paid tribute to the women who courageously broke their silence and thanked the court for taking action.

The investigation also made six recommendations which have been acted on:

* A human resources policy relevant to the personal staff of justices

* Better induction process for associates

* A support person for associates, who can act as a conduit to the chief executive and principal registrar

* Clarification that confidentiality requirements for associates relate only to the work of the court

* Associates are not obliged to attend social functions.

Justice Kiefel said the court had taken a close look at its policies and processes.

"There is no place for sexual harassment in any workplace," Justice Kiefel said.

Justice Heydon was on the bench from 2003 to 2013 and led a royal commission into union misconduct.

Australian Associated Press