Detectives have seized drugs with an estimated street value of €400,000.
A man and a woman arrested during the operation in Lucan, west Dublin, are being questioned about the cannabis find.
The haul was uncovered in a raid on a house in the Hillcrest Heights area last night.
The cannabis herb has been sent for forensic analysis.
A man in his late 20s and a woman in her early 20s were arrested at the scene.
They are being detained at Ronanstown and Lucan Garda Stations under the Drug Trafficking Act.
The arrests were made as part of an ongoing investigation into the sale and supply of controlled drugs in Dublin.
The operation was carried out by the Lucan Drugs Unit and Garda National Drugs Unit.
A Garda spokesman said: “Investigations are ongoing.”