It has emerged that Tusla, the child and family agency, sent a file containing false allegations of sexual abuse against Garda whistleblower Sergeant Maurice McCabe to gardaí in 2013.
Sgt McCabe was not informed that the Tusla file contained this allegation, RTÉ's Prime Time reports.
In April 2014, social workers in Tusla opened files in the names of each of Sgt McCabe’s children. All four files included the allegations of sexual abuse.
On 14 May 2014, a counsellor contacted Tusla to say she had made "an administrative error" in her report to them.
The counsellor claimed that a line relating to the false abuse allegation had "been pasted in error".
Sgt McCabe learned of the accusations on 29 December 2015 when a child protection social worker wrote to inform him that he was being investigated for sexual abuse.
On 20 June 2016, the same social worker again wrote to Sgt McCabe saying a mistake had been made and no allegation of sexual abuse had been made.
Tusla has since written to the Department of Children, acknowledging that an error occurred and that an internal case review had been ordered.
The agency also indicated that it would apologise to Mr McCabe.
Meanwhile, Sinn Féin has called on Garda Commissioner Nóirín O'Sullivan to step aside while a Commission of Investigation chaired by Supreme Court judge Mr Justice Peter Charleton takes place.
Yesterday, Tánaiste and Minister for Justice Frances Fitzgerald agreed to broaden its terms of reference looking into claims of a campaign by senior gardaí to discredit garda whistleblowers.
Sinn Féin's deputy leader Mary Lou McDonald described the Prime Time revelations as "unprecedented ... and vile" and has questioned how the Tánaiste could not have known about contact between An Garda Síochána and Tusla, which she stated in response to a Dáil question from Ms McDonald yesterday.