Reports on investigations into all deaths in prison will be published under a new regime put in place by Justice Minister Alan Shatter, it has been announced.
The move to ensure an independent inquiry into every death follows the suicide last December of a man who had admitted killing a love rival days earlier.
Remand prisoner Shane Rogers was on suicide watch when found hanged in Cloverhill prison, Dublin, while awaiting trial for killing Crossmaglen GAA star James Hughes in a row over an ex-girlfriend.
Judge Michael Reilly, the inspector of prisons, will conduct investigations into all deaths in jails.
"I welcome this important development. Justice must not only be done, it must be seen to be done," Mr Shatter said.
"There can be no questions left unanswered when a person in state custody dies. The independence and track record of the inspector speaks for itself and I am confident that the Irish Prison Service and other relevant public sector agencies will co-operate with and indeed welcome the inspector's involvement in this area."
The minister said the independent inquiries will be in addition to garda investigations and coroner inquests and they will not prejudice either.
The inspector, who has been reviewing Rogers' death, will also examine prisoners who it is believed die from natural causes. The deaths of prisoners who are on temporary release will be included in the new regime and the inspector will have the power to consult the next of kin. The inspector is obliged to publish all reports, the Department of Justice added.
The Irish Penal Reform Trust (IPRT) said the reform was highly significant. But Liam Herrick, executive director of the IPRT, said prisoners' families would have to wait to see if it meets requirements under the European Convention on Human Rights.
"Questions remain over whether the inspector will have the powers to compel witnesses to give evidence; what level of involvement families of the deceased person will have; and whether, in the most serious of cases, a public inquiry will be possible," he said.