A protocol aimed at strengthening ties between the police on both sides of the border comes into effect today.
The Minister for Justice, Mr O'Donoghue, and Northern Secretary Dr John Reid will sign an agreement at Stormont later today aimed at improving communications links between the new Police Service of Northern Ireland and the Garda.
The accord, which arose out of the Patten Commission's police reform recommendations, will enable the exchange of personnel on both sides of the border.
It will also allow the lateral entry of gardaí into the police in the North in a bid to address religious imbalance the Police Service of Northern Ireland (PSNI) inherited from the RUC, whose membership was overwhelmingly Protestant and unionist.
Lateral entry was a key demand of the SDLP negotiators last year in return for them supporting the PSNI and taking their seats on the Policing Board.
The agreement has been welcomed by SDLP chairman Mr Alex Attwood who sits on the Policing Board: "This is further evidence of the new beginning to policing and creates the prospects of Garda officers having a full role and full powers within the PSNI.
"Greater co-operation between the police services is essential internationally and it is now being developed way beyond other exchange agreements involving the PSNI and Gardai," he said.
PA