Ten soldiers have tested positive for drugs since compulsory checks were introduced in the Defence Forces three years ago, the Dáil was told.
Minister for Defence Willie O'Dea said the target of testing 10 per cent of personnel had been reached, and since compulsory checks started in November 2002 a total of 2,418 soldiers of all ranks had been tested.
The 10 positive cases represented "less than half of 1 per cent" which the Minister said "we're all very pleased and very happy about".
The primary aim of the testing was deterrence, and "to provide a credible level of deterrence" a target was set to test 10 per cent of personnel, he said during Defence Questions.
"While there have been relatively few instances of drug related problems in the Defence Forces, it is recognised that the Defence Forces as a component of the wider community, mirror the community at large," Mr O'Dea said. "The implications of drug abuse in an organisation where personnel have access to firearms are too obvious to require elaboration," he added.
Under the regulations, a soldier who refuses to provide a sample or who tests positive "is liable to retirement, discharge or relinquishment of commission or withdrawal of cadetship if appropriate".
Labour's spokesman Joe Sherlock said that "given the work the Defence Forces carry out and the access that personnel have to weapons", there "can be no toleration of drug taking".
But he added that "on the basis of testing so far there is no evidence of any significant drugs problem in the Defence Forces".
The Minister agreed that "it is absolutely imperative that there be no drug abuse problem in the Army. That is why the scheme was introduced. It is there as a deterrent."
Gerard Murphy (FG, Cork North-West) asked the Minister if passive smoking of cannabis could result in a positive test and what the consequences were of that. Mr O'Dea said that such passive smoking "could theoretically give rise to a positive test".
He said that if a soldier tested positive they would be "stood down immediately" but "there is an appeal procedure there and people must be given the benefit of the doubt if they have a good defence".
Asked by Finian McGrath (Ind, Dublin North-Central) what the reaction of personnel had been to the introduction of testing, the Minister said it was "very good, very positive.
"The ordinary members of the permanent Defence Forces do not want people who are relying on drugs in their midst." But he added, whether the reaction was "positive or negative, the test is compulsory".
Before the scheme was introduced there was widespread consultation about the substance abuse programme, he said.
Personnel were randomly selected to test for controlled drugs, which are described as "any substance, product or preparation declared by order of the Government to be a controlled drug", he added.