Operation Spire saw 10,000 searches carried out on O'Connell Street in 2014.
The garda operation focused on O'Connell Street and its surrounding area of Henry and Marlborough Street and, as a result of the searches, 611 incidences of illegal drugs for sale and supply were uncovered.
On top of this, 511 cases of possession of drugs were detected - but these were not for actual sale.
A total of €10,000 in cash and 154 mobile phones were seized, for the purpose of the sale and supply of drugs, during searches.
A total of 496 charges came about as a result of the arrests. Across the northern part of the city centre, beyond the reach of Operation Spire, 6,000 more searches were carried out by gardai in 2014.
A total of 14,290 prescription tablets were seized.