TAOISEACH Enda Kenny says most of the allegations of garda wrongdoing are "groundless", despite setting up an investigation into the claims.
However, Mr Kenny did admit the spate of controversies surrounding the Garda Siochana had served to "undermine" public confidence in the force.
The Government has ordered a review by a barrister of the claims made by garda whistleblower Sergeant Maurice McCabe. But Mr Kenny said the cases were already examined by the Garda Siochana and the Director of Public Prosecutions and 11 of the 12 cases were found to be "groundless".
The review will be conducted by Sean Guerin, who has represented the State in a number of high-profile murder cases.
The Cabinet also announced an overhaul of the garda complaints system by the summer, which will see a new law allowing gardai to bring their complaints directly to the Garda Siochana Ombudsman Commission (GSOC).
The terms of reference of Mr Guerin's review are expected to be published today. He will have the option of recommending the establishment of an independent inquiry into Sgt McCabe's allegations, as called for by the Opposition.
Mr Shatter will also spend a lengthy session in the Dail today giving a "chronology" of what actions his department took since it received Mr McCabe's allegations two years ago.
Mr Guerin's review will now take place alongside an inquiry by retired high court judge John Cooke into the Garda Ombudsman bugging controversy.
However, it's understood its remit will not extend to a dispute between Sgt McCabe and Garda Commissioner Martin Callinan over a directive issued to the serving officer in December 2012.
Sgt McCabe reacted furiously to allegations he did not "co-operate" with an internal garda inquiry into the quashing of penalty points. And he released a transcript of an alleged conversation between him and a senior officer which he claims proves he was never asked to co-operate with the inquiry.