Specialist national and local units seized four firearms and up to €3m worth of heroin and cocaine in Tallaght, south-west Dublin, on Wednesday night.
The weapons comprised an AK47 assault riffle, a loaded pump-action shotgun and two rifles with telescope sights, along with silencers and associated ammunition.
The seizure, the result of an intelligence operation, was conducted by the Garda Drugs and Organised Crime Bureau and the Tallaght Drugs Unit.
The Irish Examiner understands the joint investigation had identified a lock-up in the Greenhills area and secured a search warrant last Sunday.
A surveillance operation on the warehouse was set up, as officers waited for someone to arrive.
On Wednesday night, at around 7pm, a car approached the lock-up. When the two passengers attempted to drive away, armed gardaí swooped on the vehicle.
Inside, they discovered the weapons arsenal.
One source said the scale of the cache was “worrying” and that the firearms would have been used in gangland shootings.
Gardaí arrested the two men, aged 41 and 34. One was from the north inner city and the other from Tallaght.
They are not thought to be significant players. They were charged last night and are due to appear in court this morning.
When gardaí searched the warehouse they discovered a significant consignment of drugs. It comprised 29kg of cocaine, with an estimated street value of over €2m, and 6kg of heroin, worth around €900,000.
The drugs could be in high purity and their final street value, once diluted, may be multiples of €3m.
Gardaí are satisfied the guns and drugs belonged to a major gang headed by a 43-year-old Ballyfermot man.
While this individual has escaped convictions for drug offences, he has been one of the top target of the Garda National Drugs Unit for many years.
The GNDU was subsumed along with the Organised Crime Unit into the new Drugs and Organised Crime Bureau earlier this year.
The gang boss was released last year from prison. He has previous convictions for assault, criminal damage, and larceny.
A feud between his gang and another rival drug trafficking outfit has claimed the lives of at least four people, all of them in 2009 and 2010.
The gangs, and affiliates, dominate the lucrative drug trade in Ballyfermot and Clondalkin.
Gardaí are concerned that the gun arsenal may be a sign of renewed gangland violence in the area.