The former Garda Commissioner is giving evidence at the Disclosures Tribunal
Noirin O'Sullivan says she was setting the tone from the top in relation to supporting Maurice McCabe when she was appointed interim Garda Commissioner in 2014.
Ms O'Sullivan has been giving evidence at the Disclosures Tribunal, where she said it was her job to restore public confidence in An Garda Síochána when she took up the job.
The tribunal is examining whether she relied on unjustified grounds to discredit Sergeant McCabe at the O'Higgins Commission.
The Disclosures Tribunal has already accepted that Ms O'Sullivan did not rely on a false allegation of sexual abuse to smear Maurice McCabe at the O'Higgins Commission of investigation into policing matters in Cavan-Monaghan.
But the tribunal is still trying to establish if the then-Garda Commissioner relied on other unjustified grounds to discredit him.
Ms O’Sullivan says on her appointment as interim Garda Commissioner in March 2014, she set about restoring trust and confidence in the force.
She said she also wanted to make it clear that whistleblowers should be supported.
Ms O'Sullivan said that the delays in hiring counsel and supplying documents to for the O'Higgins Inquiry were unsatisfactory, but accepted that some of the responsibility for those delays lay with her.
She also said that she hoped the inquiry would get to the truth of the matter by establishing relevant facts against the backdrop of a public narrative that the force was corrupt and that it had lost public confidence.