Former High Court Judge Iarfhlaith O'Neill has been appointed to oversee an inquiry into allegations of a smear campaign against whistleblowers in the Gardaí.

Two senior officers claim they were directly involved in the smearing of a whistleblower.

Minister Frances Fitzgerald has ordered an investigation and this evening outlined its terms of reference.

Justice O'Neill will carry out a review into allegations of wrongdoing and report back within six weeks.