The Morris tribunal reports suggested "very serious systemic problems" in the Garda Síochána, Garda Ombudsman Commission member Conor Brady has said.
Mr Brady said the reports suggested that, as well as good and bad members of the force, there was "a great body of people in the middle who are capable of being led either way, and that in this instance it seems as if the people in the middle certainly didn't support the people on the side of right, and tended if anything to go towards the people who were doing things the wrong way".
Speaking on RTÉ's Morning Ireland, Mr Brady said this suggested "very serious systemic problems in an organisation".
"Every organisation will throw up its bad ones, but the organisation should be able to withstand that and it should have self-correcting mechanisms to isolate the bad ones.
"But it seems that in this case, the Morris tribunal came to the conclusion that that didn't happen and that in fact the virus spread, as it were."
Responding to Mr Brady's comments, the secretary general of the Garda Representative Association, PJ Stone, said members of the commission, which will operate from next year, should not speak publicly in a way that could undermine officers' trust in the new body.
Mr Stone said public comment from members of the Garda Ombudsman Commission "would, in my view, dent confidence in my members' ability to see them carrying out the role in an independent and constructive way".
He said the Morris tribunal reports, the latest of which were published last week, had caused pain and hurt among rank-and-file gardaí. "[The reports] have an effect of members out there who are not directly affected by what happened in Donegal feeling the pain and the hurt of that."
Gardaí did their work in difficult circumstances, Mr Stone said, and he was concerned that certain practices in Donegal might be assumed to be typical of the force generally.
"I'm not here to defend the indefensible in Donegal," he said. "I am very, very sorry for what happened in Donegal, but it happened 10 years ago. I don't believe it will happen again.
"We have to accept that people in Donegal in all ranks acted irresponsibly. Let's not take Donegal as being the norm right across the country."
Mr Brady also said that in England and Wales there was a move away from attempting to have policemen convicted before juries and towards seeking to have them dismissed instead. "I think that is probably the way things will go here too," he said.
"The difficulty of getting convictions from a jury is clear. Juries are very reluctant. You saw it in the May Day protests, where people were seen on television doing unspeakable things, and they were acquitted by a jury."
"I think that probably the way forward will be by way of a disciplinary system which is close to the normal industrial relations model rather than the traditional police disciplinary model," Mr Brady said.
From next year, the Garda Ombudsman Commission replaces the Garda Complaints Board, and has a substantially expanded role than that of the board. As part of that role, it is required to directly investigate complaints against members of the Garda Síochána.