The most senior civil servant in the Department of Justice has defended the advice given to the former justice minister Frances Fitzgerald in relation to the legal strategy deployed by gardaí before the O'Higgins Commission.

Oonagh McPhillips told the Oireachtas Justice Committee that the department's advice to a minister would consistently be that they should not be involved in any way in a case to be presented by another party before a commission of investigation.

She said: "The department's view remains that where a justice minister established a commission of investigation into alleged wrongdoing on the part of An Garda Síochána, it would be wholly wrong for that minister to involve themselves in the case or evidence to be presented by any of the parties.

"Indeed it seems clear that if a commission became aware that the Garda was behaving in such a way, this could have very serious consequences" she said.

However, under questioning from Fianna Fáil's Jim O'Callaghan about an email sent to Ms Fitzgerald informing her of the adversarial approach being taken by the legal team for the Garda Commissioner in relation to Sergeant Maurice McCabe, Ms McPhillips accepted that the minister would have done nothing wrong if she had discussed this email with her own officials, and expressed her dissatisfaction with the approach.

"She could express that view, but the advice from the department would be that there's nothing you can do about it", Ms McPhillips said.

Earlier, Ms McPhillips told the committee that considerable progress has been achieved on the delivery of the Toland Report on reform of the Department of Justice.

She said the senior management team and former secretary general Noel Waters had engaged fully with the Toland report.

Ms McPhillips said there is no doubt that the people who make up the department make mistakes.

"I would not for one moment conclude that the advice that the department gives cannot be questioned.

"One of our own objectives in recent years has been to encourage questions, and to challenge and test assumptions more robustly," she said.

"At every level in the organisation there are hundreds of talented people trying to provide the best public service they can" she added.  

The Assistant Secretary at the department told the committee that there was "no general widespread trawl of documents through the department" on foot of a discovery order by the Disclosures Tribunal.

When asked if such a trawl was discussed when the discovery order came in, John O'Callaghan replied, "I'm not sure it was actually considered".

Responding to Fianna Fáil's Jack Chambers, he said the people who were dealing with the tribunal were staff who were fully au fait with other related inquiries.

He said there was no electronic trawl of documents, until recent weeks.

Ms McPhillips said there are many thousands of documents in the Department of Justice that mention the people involved over the last five years.

"If we were to take a totally wide-ranging view of all of that stuff and land it down to Dublin Castle, I don't think that would be of assistance to the tribunal" she said.

She said the three discovery orders which came from the tribunal looked for specific information, and they were complied with in full.

Ms McPhillips said it was a matter of regret to her that the Taoiseach felt he was not fully briefed by the department when he responded to questions about the email controversy in the Dáil.  

However, she said, she did not agree with his assertion that the department was dysfunctional. 

Labour TD Alan Kelly told Ms McPhillips that it was very alarming that the deparment did not provide information that subsequently surfaced in relation to the Sgt McCabe.  

Ms McPhillips insisted the department was not withholding information and they complied in full with the text of the discovery order.  

Mr Kelly said the department should have voluntarily offered to supply other material to the tribunal.  He said it was "extremely worrying" that there may be other relevant information with the department. 

Chair of the Committee, Sinn Féin TD Caoimhghín Ó Caoláin, said the trawl, if it had been targetted, would have thrown up the most recently discovered emails.

He said the committee believed the department should have carried out an electronic trawl and it should be the tribunal's to determine relevance.

Ms McPhillips agreed to a request from Mr Ó Caoláin to ask the tribunal if they required a further targetted trawl.