The Garda Commissioner has moved to reassure the Policing Authority that the use of a commercial email service by herself and other gardaí did not represent a threat to security.

Commissioner Nóirín O’Sullivan insisted the garda's systems were secure and that security had not been compromised.

However, members of the authority told senior garda management at a public meeting today that they had examined the garda's policy on the use of outside email and that it had been breached.

Today was the first opportunity for senior garda management to publicly address the controversy over the commissioner's use of a commercial email system for garda business.

The Policing Authority told her it was an issue of concern.

Chairperson Josephine Feehily said it was more about public confidence rather than the technical details and the authority was seeking an assurance in relation to how people's information was handled and the security of the State.

Authority members also examined the garda's policy of the use of private emails for garda business.

Maureen Lynott said it was "prohibited", that the policy was very tight and that therefore it had been breached.

In light of the fact that Gmail was installed on garda devices, Valerie Judge asked were the gardaí aware of security.

Garda management insisted, however, the root of the problem is that the policy which was devised in 2012 is out of date.

Chief executive officer Joe Nugent insisted that the issues did not represent a threat to security but the policy has not kept pace with technology.

He said Gmail was installed on devices supplied and protected by An Garda Síochána and it was not possible on the existing garda email to access certain file types.

Work, he said, to change the policy had commenced.

The Garda Commissioner moved to reassure the authority that there had been no threat to security.

The commissioner also welcomed the appointment this week of 11 senior officers but said there were still critical vacancies which needed to be filled.

In addition, she said, there would be at least another 14 critical senior positions, including three assistant commissioner positions, vacant by the middle of next year.

Judge gets more time for whistleblower claim probe

Separately, a judge investigating allegations that Commissioner O'Sullivan was part of a campaign to discredit a whistleblower has been granted more time to complete his report.

Two gardaí claimed in protected disclosures that Ms O'Sullivan and other senior garda officers were aware of a campaign to damage the credibility of Garda Sergeant Maurice McCabe.

One of the gardaí, Superintendent David Taylor, a former head of the Garda Press Office, told Sgt McCabe that he took part in this alleged campaign.

Sgt McCabe has made allegations of garda misconduct and poor practice, some of which have been upheld, while others were rejected by the O'Higgins Commission.

The commissioner has already said she was not privy to or did not approve any action designed to target gardaí who make protected disclosures and would condemn any such action.

The Government appointed Mr Justice Iarfhlaith O'Neill to review the allegations made in the protected disclosures and recommend further action if necessary.

The Tánaiste has acceded to the judge's request for an extension until 2 December to submit his report.

It was due to be completed yesterday.

The judge is also examining a separate complaint submitted by the civilian head of An Garda Síochána outlining another garda's allegations.

The review has already been criticised by Independents4Change TD Clare Daly and legal representatives of another garda whistleblower, Keith Harrison.

Minister for Justice Frances Fitzgerald has said that upon receipt of the report she will consider what if any further steps should be taken.