The Minister for Justice has said it is disturbing that a tribunal is necessary to investigate allegations against gardaí in Donegal.
Mr McDowell said the Morris inquiry announced earlier this year would not have been established if the Government "weren't seriously concerned about the political events, the sequence of revelations and the substance of those revelations.
"And without working out where the truth exactly lies, the very fact that the allegations could be credibly made and that a tribunal of inquiry is necessary is disturbing enough in itself."
Mr Justice Morris, former High Court president, was appointed last February to head an inquiry into allegations of serious criminal and corrupt activity by certain gardaí in Donegal.
Mr McDowell made his comments in an RTÉ radio interview yesterday, when he said he was "absolutely determined" that the Garda would uphold the highest standards.
He agreed the Donegal case raised "a can of worms" about the Garda.
On the issue of non-jury courts, the Minister said he did not believe in deviating from jury trial "except where it's absolutely necessary".
The protection for juries should be strengthened where necessary, he added.
Mr McDowell said the non-jury Special Criminal Court should "remain for the time being because there is a very significant subversive threat still in existence in this State, and anybody who thinks they have gone away, you know, is very mistaken."
The Minister also said he had no intention at the moment of legislating on abortion in line with the Supreme Court ruling in the X case following the recent referendum.
"The Taoiseach suggested in the aftermath of the last referendum that it was a matter he didn't intend to revisit in the short term, and I don't think there is any appetite in Government for a second bite at that issue," he said.
Meanwhile, in a newspaper article yesterday, Mr McDowell said the legal obligation to give refuge to asylum-seekers in Ireland fleeing persecution was matched by "an equally clear legal and political imperative to deny access to those who break our law by pretending to be refugees when in fact they are economic migrants who are queue-jumping.
"It may be uncomfortable for some to make that distinction. It is much more politically correct to ignore that distinction. It certainly suits a particular mind-set to blur that distinction or drown it completely in rhetoric of compassion," he wrote in the Sunday Independent.