President Mary McAleese signed the controversial Criminal Justice Bill into law last night.
Earlier, she had held a meeting of the Council of State to consider whether the measure should be referred to the Supreme Court for constitutional testing.
The act provides for more powers for the gardaí and tougher sentencing, as well as restrictions on bail.
In addition to some of the more controversial provisions, some opposition TDs complained that the Bill was rushed through the Dáil.
The bill was opposed by Sinn Féin, the Greens and a number of Independents, while Fine Gael and Labour abstained.
