The Minister for Justice has warned judges to apply sentencing law in relation to drug-dealing offences.
Mr McDowell expressed disappointment that the judiciary rarely used the mandatory 10-year sentence, which was not being applied with the "vigour" the legislature expected.
Exceptions were "provided for in exceptional cases, but it seems that the exception is when the wish of this House is complied with", he said of the law the Oireachtas passed making a 10-year prison sentence mandatory for anyone convicted of possession of drugs for supply with a value greater than £10,000 (€12,700).
The Minister also reaffirmed the Government's commitment to creating drug-free prisons rather than just drug-free units in prisons. "There is no acceptable level of drugs in prison."
Answering Justice questions in the Dáil, he said he was "disappointed that the judiciary has not taken to it in the way the House had intended, nor is it being applied with the vigour the House had expected it would be".
And he warned that the judiciary collectively "should have regard to the proposition this House put before it, that for possession of drugs with intent to supply on a commercial basis, as defined in that statute, the norm was to be a 10-year sentence and that only in exceptional cases identified by the judiciary should there be a lesser penalty".
He added: "That has not happened, but that is something to which I will come back, because I do not propose to lose sight of it."
Fine Gael's spokesman Mr John Deasy said the level of charges against people for possession of drugs with intent to supply had fallen rather than increased. That meant "the message is not getting through to the people on the ground that there is a deterrent in place". It was clear that "the 10-year so-called minimum sentence brought in a few years ago has not been enforced by judges". He pointed to his party's suggestion of a three-month minimum sentence for a first offence of possession of drugs with intent to supply. He also stressed that many people ended up in jail because of drugs-related offences.
There were 1,530 cases of possession of drugs with intent to supply in 2002, and 358 convictions, while seizures by gardaí and customs and excise had risen to €121 million last year.
The Minister said the Government's commitment to "mandatory testing of prisoners and creating drug-free prisons, as opposed to drug-free units in prisons, is the way forward".
"The notion of providing sterilising fluid and needles in prison to abusing prisoners is anathema as far as I am concerned. I am not going down that road no matter what case is made for it."