The cabinet has signed off on the draft terms of reference for the new Tribunal into the alleged mistreatment of Garda whistleblowers.

The Terms of Reference are to be put to the Dáil this afternoon, and the Seanad this evening, so that the inquiry can be set up as soon as possible.

It's also been confirmed that the Supreme Court judge Peter Charleton, who was due to chair a Commission of Investigation on the subject instead, is now to chair the Tribunal.

This morning the Taoiseach told an Oireachtas committee that Charleton still believed the primary work of the Tribunal, investigating the alleged smearing of Sergeant Maurice McCabe, can be carried out in 9 months.

Following concerns raised by Fianna Fáil's Jim O'Callaghan about the possibility that the Tusla file on Maurice McCabe might not be covered by the existing terms of reference, an extra heading has been included to explicitly examine the circumstances of how the file was created - and whether it was used by Gardai for malicious means.

The inquiry will also investigate allegations by another Garda whistleblower, Keith Harrison, who claims he too was mistreated after making protected disclosures.

The Tribunal will also have the scope to investigate the allegations of other whistleblowers, who have already come forward and alleged mistreatment, once the other two cases have been investigated.