Fine Gael and the Irish Council for Civil Liberties (ICCL) have expressed concerns about the powers that could be given to the proposed Garda reserve who have only 24 hours training.
The president of the Association of Garda Sergeants of Ireland (AGSI), Joe Dirwan, has described plans to create a 900-strong reserve by next September as a "mad hatter" scheme.
Powers of arrest are due to given to reservists after a training programme which amounts to just 24 hours - a proposal which is arousing apprehension beyond the AGSI.
Mr Dirwan has also expressed concern about issues such as reservists' safety and discipline, access to confidential information on the Garda's Pulse database and the potential for them to settle "old scores under the pretence of police action".
ICCL senior research and policy officer Tanya Ward today said police powers should only be conferred on fully trained members of the Garda.
Ms Ward noted that new members of the force undergo over one year of training and are not considered full members for another two years, and she referred to the Human Rights Commission's "grave reservations" about affording police powers to volunteers.
"The Minister's proposals are designed to avoid increasing the size of the service. This is policing on the cheap, and has proved to be no more than that in other jurisdictions," Ms Ward said.
Fine Gael justice spokesman Jim O'Keeffe said Mr McDowell was planning to use the reserve as a means of manipulating figures on Garda numbers. He supported the principle of a reserve force -
but only one which carried out "routine" duties that releases full-time officers to carry out "front-line duties.
"However, the plans for a reserve force as unveiled by the Minister could create a poorly trained state force with almost the same powers as a regular Garda . . . . Fine Gael believes that any such force should have proportional powers and be properly trained."
Minister for Justice Michael McDowell yesterday pledged to press ahead with plans for the reserve, and said 900 would be recruited by the end of the year.