Lieutenant-Colonel Kerry Haggar denied she was trying to intimidate the whistleblower just weeks before the woman was due to give evidence at the commissions' public hearings into abuse within the Salvation Army.

Colonel Haggar, formerly a member of the Salvation Army's senior cabinet, broke down while giving evidence before the royal commission on Monday.

She apologised for sending the message to Captain Michelle White, who had gone to the Office of the Children's Guardian and the Ombudsman in 2013 and reported that Colonel Haggar's husband, Colin Haggar, had assaulted a young girl in 1989.

"I'm incredibly sorry and I'd like to reiterate publicly to Michelle my apologies for sending that," Colonel Haggar said, after describing the message as "unwise".

"It was - sorry. It was a very personal reaction out of my own distress."

The message was sent just two weeks before Captain White was due to give evidence before the commission.

It attacked Captain White for blowing the whistle about her husband's behaviour and the subsequent failure of the Salvation Army hierarchy to act.

"The chain of events you have set in place have caused devastation and considerable pain to many innocent people," Colonel Haggar said in the message.

Colin Haggar assaulted the girl on at least one occasion but has never been charged and was stood down only last month after the royal commission's hearings had begun.

The commission has previously heard that, after the abuse, Haggar admitted it to the girl's mother.

Colin Haggar claims that he then confessed the assault to the police some years later and that he was told by officers that nothing could be done.

However, the state of NSW, which is represented at the commission, denies such a confession was ever made.

On Monday, the chairman of the royal commission, Justice Peter McClellan, put it to Kerry Haggar that the message she sent to Captain White was "very serious", alluding to the fact that attempting to intimidate a witness at the royal commission was a criminal offence.

Colonel Haggar denied she was attempting to intimidate her colleague.

"I didn't at the time, but only since when Michelle gave evidence at the royal commission, I realised that it could be viewed as intimidatory and potentially a criminal offence," she said.

"I wasn't aware of that at the time.

"There was no intention to intimidate."

Colonel Haggar told the commission that she had been stood down from her role as the head of business administration for the Salvation Army and had been told that she would not be returning to that role.

The hearing continues.