Nóirín O'Sullivan is expected to clarify advice given to her legal team concerning the whistleblower Maurice McCabe, whose claims of Garda corruption helped lead to the formation of the O'Higgins Commission.
Questions have been raised over whether the Garda Commissioner instructed her counsel to attack Sergeant McCabe's integrity at the inquiry.
Yesterday Nóirín O’Sullivan said her lawyers were never instructed to question his integrity, or to make a case he was acting maliciously.
The controversy has drawn criticism of the Garda Commissioner who's been accused of supporting Garda whistleblowers in public, while privately criticising them.