Detectives have been questioning three men over the seizure of cannabis resin worth 200,000 euro.
The suspects were arrested by officers targeting the sale of drugs in Co Louth and north Dublin who stopped two vans in Cocklehill, Blackrock and Dundalk.
Gardai said approximately 38kg of cannabis resin was found in one of the vans.
A third vehicle - a car - was stopped and searched nearby and a significant amount of cash was recovered.
The three drivers, aged 28, 32, and 63, were taken to Dundalk and Drogheda garda stations where they are being questioned under section 2 of the Criminal Justice Drug Trafficking Act 1996.
A Garda spokesman said four more follow-up searches were carried out in Dundalk and Coolock, where a smaller amount of cannabis resin, approximately 1kg, and more cash were found at one address.
"The potential street value of both seizures is believed to be in excess of 200,000 euro, subject to analysis," he said.
Meanwhile, a 54-year-old Vietnamese man remains in garda custody after hundreds of cannabis plants and herb, worth 500,000 euro, were seized in Co Meath.