Gardai have found a submachine gun and 4 handguns in a discarded backpack in Coolock.
The discovery was made after officers chased a suspect in his 20s who was stopped during a routine operation.
The suspect fled the vehicle he was driving and discarded the backpack where the arms were found.
The vehicle believed to be linked to the investigation has been seized by gardai and the firearms will be forensically examined.
Gardai are still searching for the suspect and say investigations are continuing.