Garda Keith Harrison, one of the whistleblowers to be covered in the Charleton Tribunal of Inquiry, has welcomed his inclusion in the investigation.
He said he has had a "long and difficult battle" to have his complaints investigated.
Garda Harrison added that he trusts the inquiry will establish the truth.
The Dáil yesterday agreed, without a vote, the terms of reference of the inquiry, which will investigate an alleged smear campaign by senior gardaí against Sergeant Maurice McCabe.
The inquiry also will include other garda whistleblowers.
The allegations against Sgt McCabe will be prioritised and an interim report will be published in three months.
Concerns raised over tribunal model
Social Democrat TD Róisín Shortall has said she fears "we will regret the rush to pass the terms of reference through the Dáil".
Speaking on RTÉ's Morning Ireland, Ms Shortall said the format that is being established "opens up the possibility of a long-running and expensive tribunal" that is not going to get to the root of what it is alleged to have occurred to Sgt Mc Cabe.
She said there is a public demand for answers at an early stage and the fear of a tribunal is that is closes down any discussion or answers from Government.
She said the tribunal model is not the best way to investigate the allegations appropriately.
Ms Shortall has said that there is provision for the Garda Síochána Ombudsman Commission to carry out a public interest investigation with external police officers to give answers in the short term to some of the questions of concern posed by Sgt McCabe.
Ireland needs an anti-corruption agency to investigate matters like this, she said. She said people want to see those responsible brought to book and held responsible and this tribunal will not do that.
She also said reforming legislation should be looked at again concerning the length of tribunals, expenses and the right to legal representation.
