The controversial Act reforming the Garda Síochána forced through the Dáil last month could be unconstitutional, according to the Garda Representative Association (GRA).
The Minister for Justice revealed today that President McAleese signed the Garda Síochána Act (2004) into law on Sunday.
Effective in part from Friday, the Act provides protection for gardaí who blow the whistle on corrupt colleagues and empowers the Garda Commissioner to sack any members of the force up to inspector rank.
Opponents say the legislation, the first major revision of the operation and accountability of the force since the foundation of the State, is excessive and could be open to legal challenge.
The GRA has said the accountability measures could compromise its members' constitutional rights. In a statement issued this afternoon, it said High Court decisions supported their view and that it had put this to the Minister in all its submissions during the consultative stage.
"On the basis of previous High Court decisions, that there are serious constitutional questions raised if members are asked to account for their actions without being informed that such an account may be used against them in a criminal case.
"The GRA’s views on this matter have been upheld by Irish courts.
"In a case where gardaí who gave an account of their actions and were subsequently dismissed, the court ruled that unless gardaí were advised of the consequences of that admission they should not have been asked to give that account unless advised of its consequences," the GRA said.
Speaking on RTÉ television today, Mr McDowell said he did not see "any major difficulties" in relation to the issue. "I think that on balance everyone on reflection would think it’s a huge improvement that there is such a provision in place."
It will be some time before other provisions of the legislation come into effect, and Mr McDowell hopes to have a report from the Implementation Advisory Group established to assist in effecting the far-reaching reforms by the end of the year.
But a number of important provisions come into operation on Friday. Among these is the requirement for the Garda Commissioner to be fully accountable to the Minister for Justice.
Under this provision the commissioner must supply the Secretary General of the department with any document in his power or control. Labour Party leader Pat Rabbitte has described the provision as a "threat to democracy".
"[Mr McDowell] and his successors are in future to be given access on demand to any and every Garda file, about any and every, person, body, place or thing. This includes access to files on themselves and their personal or political friends and enemies," Mr Rabbitte said.
The section was inserted in response to the failure by then Garda Commissioner Pat Byrne to provide Mr McDowell and predecessor John O’Donoghue with full access to an internal Garda investigation into officers accused of corruption in Donegal.
The report later provided the basis of the Morris tribunal, which has issued two scathing reports on Garda conduct in the division.
There has also been widespread criticism of the Minster’s failure to create a position of Garda ombudsman along the lines of that in Northern Ireland. Instead a three-person committee will head an inspectorate that is answerable to the minister.
The body will be known as the Garda Síochána Ombudsman Commission but will not have the powers of its Northern counterpart and far fewer staff. Recruitment has already begun, and the Minister hopes to make a further announcement on it soon.
The new legislation also provides for enhanced co-operation between the Garda Síochána and police services abroad.