Five people have been arrested after heroin and cocaine with a combined estimated street value of €6.3m was seized in two separate raids in Dublin and Co Louth.
Three people were arrested after heroin with an estimated street value of €4.05m was seized in Drogheda, Co Louth.
The seizure of 27kg of the drug was made when gardaí stopped and searched an articulated truck on the M1 last night.
A 40-year-old man and a 43-year-old woman were arrested at the scene.
A second man, aged 40, was arrested in a follow-up search.
The three are being detained at Coolock and Drogheda garda stations.
Meanwhile, two men have been arrested after cocaine with an estimated street value of €2.24m was seized from a house on the Stillorgan Road in Donnybrook.
Gardai seized 32kg of the drug at the house last night.
Two men, aged 27 and 37, were arrested at scene and are being held at Blackrock Garda Station.
Gardaí described the seizures as being very significant, adding they will act as a deterrent to the drug trade.
Acting head of the Garda National Drugs Unit, Detective Chief Superintendent John O'Driscoll, said the heroin seizure was the largest for five years and the cocaine the largest since 2012.
Mr O'Driscoll said the seizures were not linked but he said the extent to which organised crime was involved was central to both investigations.