Senator Maurice Hayes, who has been appointed by the Government to oversee the implementation of Garda reforms, has said that the current proposals may not provide the body with sufficient powers in light of the second Morris tribunal report.
He also described the proposed structure of the new body, to be called an ombudsman commission, as being flawed.
Under plans contained in the Garda Bill, which is expected to pass into law by the summer, the Government will establish a new three-person Garda Ombudsman Commission, which will investigate allegations against gardaí and will have its own independent investigation staff.
However, Mr Hayes said the fact that the new body will be a three-person commission, as opposed to a sole ombudsman, could make it less effective.
"How will an ombudsman commission make their decisions, I mean, do they vote on it or not?" he asked. "I could see a chief ombudsman and a couple of deputies, but I think it's a very, very personal office and it should be kept personalised."
Mr Hayes said he also had concerns that the current powers for the commission would be insufficient to make it effective.
He also described as "nonsense" proposals to require the commission to notify the Garda Commissioner before carrying out a visit to a Garda station as part of an investigation.
"There's one thing which surprised me was that the proposal is that the ombudsman should virtually ask the commissioner permission before going into a police station," he said on RTÉ's This Week in Politics last night. "That's nonsense. And I think the Morris report in Donegal shows that it is nonsense. The ombudsman must be unfettered and must be able to act on their own initiative with the same powers as a high court judge."
Mr Hayes was appointed by Minister for Justice Michael McDowell to oversee the implementation of the Garda Bill, which will also establish an independent Garda inspectorate to audit the overall performance and practices within the force. He will chair the six-person committee which will oversee its implementation.
Meanwhile, legal representatives of the Government have written to solicitors for Frank McBrearty jnr with a view to reaching a settlement over his false arrest and detention for a murder that never took place.
On Thursday the Chief State Solicitor David J O'Hagan wrote to Mr McBrearty's solicitors inviting them to "attend settlement negotiations with a view to agreeing the amount of compensation and other terms of settlement".
The Government has also indicated that it would not be challenging Mr McBrearty's claims.
The case is due to go to full hearing at the High Court next week should both sides fail to reach a settlement.
Mr McBrearty declined to comment on the case, but said that he had received no offer of an apology from the State or any offer of compensation.