Sinn Féin’s Mary Lou McDonald made the claim after Mr Varadkar refused to condemn Garda boss Nóirín O’Sullivan and said she alone should decide if she acted incorrectly.
Asked about its finding that Ms O’Sullivan failed to tell the C&AG or the then justice minister about the scandal, he said “it is the judgement of the Garda commissioner to decide whether [they] should be informed”.
Mr Varadkar also refused to condemn Ms O’Sullivan’s six-week holiday.
Ms McDonald said Mr Varadkar’s comments are “unprecedented” and that he “has failed as Taoiseach”.