Drugs worth about 260 million euro were seized in the first half of the year, justice minister Alan Shatter has revealed.
And Garda figures covering the first seven months recorded 11,263 drug offences detected and 9,743 related arrests.
The successes were detailed after Mr Shatter was challenged on the law enforcement efforts being taken to prevent the cultivation of cannabis and trade in prescription drugs. "The problem of drug misuse remains one of the most challenging and complex issues faced by modern society," he said.
The seizures included a 400kg consignment of high grade cocaine found in two raids in West Dublin and Kildare at the end of June and regarded as the largest ever inland seizure of the drug in Ireland. Initially valued at 32 million euro, based on standard street valuations of 80,000 euro per kilo, when cut and mixed it is believed it would have been worth up to 200 million euro.
Elsewhere in the fight against drugs, Mr Shatter detailed the importance of Operation Nitrogen to identify and dismantle cannabis grow houses.
Last year, officers raided more than 500 drugs factories on the back of Garda intelligence. More than 26,000 cannabis plants valued at 10.5 million euro - the vast majority of which were regarded as high potency - were seized and destroyed.
"This remains a key focus of An Garda Siochana drug enforcement efforts," Mr Shatter said.
Among the major successes this year was a raid on a house in late June near Menlough, Co Galway, which uncovered 800 plants worth about 640,000 euro and this month alone 480 plants worth 380,000 euro at a house in Lobinstown, Navan, Co Meath, and a warehouse at Drumaville near Malin, Co Donegal, holding about one million euro worth of plants.
The growing illegal trade in prescription drugs was also acknowledged as an increasing problem across the country.
Mr Shatter noted the success of Interpol's Operation Pangea V which has involved the Irish Medicines Board, customs and gardai. Over one week at the end of September it targeted the online sale of counterfeit and illegal medicines and 282 packages carrying more than 120,000 tablets/capsules valued at more than 375,000 euro were seized.