Three men suspected of links to a major cannabis distribution network are being questioned.
The trio, detained in separate raids across Dublin over the last few days, can be held for a week under tough trafficking laws.
The Garda drugs squad seized about 1.4 million euro worth of cannabis when a van was stopped and searched in the on Arran Quay in the city centre on Tuesday.
The driver, a 60-year-old man, was detained at the scene after 200 kilos of cannabis resin was found in the vehicle.
In a follow-up operation late on Wednesday, a gang's suspected drug distribution warehouse was raided in an industrial estate near Rathcoole, on the western outskirts of the city.
A second man, aged 40, was arrested at the scene and another quantity of cannabis, believed to be worth about 400,000 euro, was recovered.
Gardai said a third man was arrested in connection with the seizures today.
The 23-year-old was detained in an operation in Dublin city centre and was being held at the Bridewell station.
All three were being questioned section two of the Drug Trafficking Act.