Two men arrested in Dublin yesterday as part of Operation Discovery have been released and a file is being sent to the Director of Public Prosecutions.
Two others remain in custody at Tallaght garda station.
They are still being questioned in relation to the robbery of a man on the Old Bawn Road, after which a hatchet and a quantity of cash was recovered.
Operation Discovery was launched to crackdown on robberies of cash transit vehicles following an upsurge in recent months.