Gardaí seized cocaine, cash and firearms in a planned raid in Tallaght this morning.
Officers from the Crime Task Force at Store Street Garda Station, in Dublin seized 1.25 kilos of the drug, believed to be worth up to €100,000 depending on its quality.
They also found two shotguns, cash and drug dealing paraphernalia when they searched an apartment.
"The raid followed a targeted Garda operation aimed at the supply and distribution of drugs in the north inner city," a Garda spokesman said.
A 25-year-old man was arrested during the operation and he is being questioned in Store Street Garda station under Section 2 of the Criminal Justice (Drug Trafficking) Act.
Meanwhile, in Rosslare, Co Wexford, Customs officers seized 123,000 ecstasy tablets, which they believe were destined for the Dublin market.
The drugs, valued at over €1 million, were discovered by a sniffer dog in the side panels of a Dutch-registered car which had arrived on the ferry from Cherbourg.
A man and a woman from the Netherlands, who are both in their early 20s, were arrested.
Last night officers from the National Drugs Unit seized cocaine following the planned search of a premises at Maynooth Road, Kildare last night. Detectives involved in the raid believe they have broke a major drug ring involving a well-known west Dublin dealer.
It is believed last night's seizure was made up of between 10 and 15 kgs of cocaine and 30 kgs of a mixing agent. The haul could be worth around €1,000,000, a Garda spokesman said.
Around €100,000 in cash was seized in a house in the Clondalkin area in a follow-up operation.
Three men and a woman have been arrested and are being held in various city Garda stations.