Nóirín O'Sullivan has told the Disclosures Tribunal she took the decision to step down as garda commissioner in 2017 for the wellbeing of her family and due to the impact on An Garda Síochána of the controversy surrounding allegations against her.

Lawyers for Ms O'Sullivan have been questioning her about the effect of media coverage and political debate relating to the allegations contained in a protected disclosure about a smear campaign against garda whistleblower Sergeant Maurice McCabe.

The tribunal is examining the claim by former Garda Press Officer Superintendent David Taylor that Martin Callinan directed the Superintendant to brief the media negatively against Sgt McCabe, and that Ms O'Sullivan knew about this.

Giving evidence today she again denied the claim.

Ms O'Sullivan told the tribunal there was absolutely no comfort in the fact that Supt Taylor had withdrawn some of the claims he made.

She said the situation had had an impact on herself, her family and on public confidence in the gardaí.

Ms O'Sullivan described what she called a complete bombardment of news articles from autumn 2016, and said there were constant and repeated calls for her resignation.

Ms O'Sullivan said it was absolutely untrue that An Garda Síochána was happy to let an incorrect notification of a Tusla file containing a false allegation against Sgt McCabe, which was sent to her office in 2014, sit there to be potentially used at some point in the future.

She said she had not differentiated between the allegation in that notification and what she had known of a previous 2006 allegation against the sergeant which was dismissed by the Director of Public Prosecutions.

Tribunal Chair Mr Justice Peter Charleton said it was really odd that an Assistant Commissioner was sent to interview a relative of Sgt McCabe in relation to an issue the relative had raised about the penalty points matter.

Ms O'Sullivan said it was not unusual for people to contact the Commissioner's office and for senior gardaí to become involved if people were unhappy with the way their situations had been dealt with at local level.

Ms O'Sullivan said she was not involved in the preparation of a document on Sgt McCabe which was part of materials used in meetings held to prepare for the Public Accounts Committee in January 2014.

She said the document would be a routine type of report prepared as an aide-mémoire for more lengthy files.

Ms O'Sullivan also told the tribunal she had never discussed Sgt McCabe with the Irish Mail on Sunday journalist Debbie McCann.

Ms O'Sullivan said she was not aware of visits by Ms McCann and Irish Sun journalist Eavan Murray to the home of Ms D, who made an allegation against Sgt McCabe in 2006.

The tribunal has previously heard that Supt Taylor says he told Martin Callinan and Nóirín O'Sullivan about the planned visits.

Ms O'Sullivan said she did not know why the disciplinary proceedings against Supt Taylor were dropped as it happened after her retirement.

Mr Justice Charleton asked if it was related to the pressure of circumstances and the fact that Supt Taylor was coming out as a whistleblower so it would not have "sat with PR".

Ms O'Sullivan said she imagined that would have had a bearing.

She also said her first reaction on hearing Paul Reynolds' broadcasts on the-then unpublished O'Higgins Commission report on RTÉ News on 9 May 2016 was to question where the information had come from. 

She also thought the focus was wrong and it was the wrong tone and An Garda Síochána needed to apologise and accept failures.

Ms O'Sullivan also said she thought Sgt McCabe was genuinely motivated by a desire to improve policing.

She also said she shared Martin Callinan's concern about how citizens' information was being put into the public domain by Sgt McCabe.

She said she thought Supt Taylor and Martin Callinan had a very close working relationship but not a personal relationship.

She said Supt Taylor "inserted" himself around Mr Callinan and the Commissioner came to rely on him.

She thought Supt Taylor was undermining her and Andrew McLindon, the garda head of communications and the superintendent did not have her back. 

She thought he was divisive and those divisions meant the press office was not working well.

Ms O'Sullivan has now concluded her evidence to the tribunal.