The Disclosures Tribunal has heard heated exchanges between its Chairperson and the Crime Correspondent with the Mail on Sunday.
Debbie McCann has repeatedly claimed privilege over her conversations with Superintendent Dave Taylor, causing judge Peter Charleton to say a reasonable person might see it as a smokescreen.
The Tribunal is currently examining a claim by Supt Taylor that he was ordered by garda management to smear Maurice McCabe.
Debbie McCann told the Tribunal for the first time today that she was never negatively briefed by any garda about Maurice McCabe.
But asked repeatedly to confirm details about conversations she had with Superintendent Taylor, Ms McCann claimed journalistic privilege.
Chairman Peter Charleton said it was not a question of adopting a privilege, adding that she had to give facts on which to base it, saying that unfortunately a reasonable person might see that as a complete smokescreen.
Ms McCann said she was trying to defend her career as a journalist, and help the Tribunal.
Judge Charleton said he thought that the truth was the most important value that exists, to which Ms McCann said, so do I.
Reporting by Juliette Gash