Cannabis and cocaine were also seized by Gardaí in the search
Gardaí are questioning a man in his 50s after after seizing drugs with a street value of 2.5 million euro in the south inner city area of Dublin.
The discovery was made after a car was stopped and follow up search was carried out.
The drugs were found yesterday evening after a vehicle was stopped a subsequent search was carried out on a residential premises in the south inner city.
Some 15kg of heroin, with an estimated value of €2.1m, 22kg of cannabis herb with a value of €440,000 and cocaine believed to be worth €35,000 was seized.
£43,000 in cash (sterling) was recovered along with a hydraulic press, a vacuum packing machine, communication devices and other drug paraphernalia.
Garda personnel attached to the Garda National Drugs and Organised Crime Bureau, assisted by the Special Crime Task Force were involved in the operation.
The man is currently detained under Section 50 of the Criminal Justice Act, 2007 at Kilmainham Garda Station in Dublin, he can be held for up to seven days.

Electricity Bills To Increase Next Year As Households To Shoulder Majority Of Power Grid Overhaul
Bus Éireann Confirms January Expressway Fare Increase, Cites Insurance And Fuel Costs
NTA Plans 24-Hour Bus Linking Newbridge, Naas And Dublin City Centre
Visiting Only Allowed For Critical Or Compassionate Reasons At Naas Hospital Amid Surge In Flu Cases
Turn2Me Reminds Locals Feeling Down Over Christmas Period To Avail Of Supports Available
Four Naas Car Parks Go Free For Christmas - But Illegal Parking Still Enforced, Says Council
Up to €400,000 Spent, Answers Yet To Be Published: Fianna Fáil TDs Demand Aras Bid Campaign Review
Family Member Questioned After Deaths Of US Filmmaker Rob Reiner And Wife