Gardaí attached to the Drugs and Organised Crime Bureau and assisted by the Blanchardstown Divisional Drug unit arrested a man in his 30s in connection with the huge haul.
As part of an intelligence led operation Gardaí searched a house in the Blanchardstown area of Dublin and discovered 300,000 Zopiclone tablets with an estimated street value of €600,000.
They also seized 280,000 Diazepam tablets with an estimated street value of €280,000.
Heroin worth an estimated €3,600 and Cannabis with an estimated street value of €2,400 were also discovered by Gardai.
During the course of this operation one man was arrested.
He is currently detained at Blanchardstown Gards Station under Section 2 of the Criminal Justice (Drug Trafficking) Act, 1996.