The Disclosures Tribunal is chaired by Supreme Court judge Peter Charleton.
It will examine allegations that senior Garda officers were involved in a smear campaign against Sgt Maurice McCabe.
In his opening statement, the judge said the tribunal would examine how top officers react when concerns about police performance are raised.
The centre of concern, he said, was whether such reaction had possibly not only been one of distaste, but of "active and thought-through malice".
He said there was also a question as to whether those who air concerns had been targeted in their family life.
Sgt McCabe had claimed there was corruption in the Republic's driving licence penalty points system.
He was investigated by the child and family agency, Tusla, following allegations of abuse, that were later found to be untrue.
Mr Justice Charleton said there would be two modules in the tribunal - the first will concern the responses of Garda Commissioner Nóirín O'Sullivan, former commissioner Martin Callinan and others at the highest command level to disclosures made by Sgt McCabe.
The second module will deal with members of the force who have made protected disclosures and whether they were mistreated as a result, he said.
The tribunal will abide by existing court rules, but rules of evidence will not apply, and hearsay is admissible, Mr Justice Charleton said.
He said the tribunal was expected to get on with its work and deliver results rapidly, adding that there were no preconceived notions as to "who is a villain and who is a victim".
"This tribunal is a drain on the resources of the Irish people, and it is paid for by their submission to the democratic structures of which taxation has been a central part in our tradition," he added.
"Every lie told before this tribunal will be a waste of what ordinary men and women have paid for through their unremitting efforts. Every action of obfuscation, of diversion of focus, and of non-cooperation is unwelcome for that reason."
It is expected to be some time before the tribunal begins to hear testimony from witnesses.
A tribunal will examine whether senior Irish police officers reacted to whistleblowers' allegations  with malice, its chairman has said.