Three men were arrested on the N24 at Cahir on Thursday night, during a major police operation involving elite Garda officers.
Three hand-held rocket launchers - capable of blowing apart armoured personnel carriers and tanks - were taken away for further examinations. Two cars were also seized.
It is believed the swoop followed a surveillance operation targeting dissidents.
The trio, who are aged in their 30s and are from Co Limerick, were being questioned at Clonmel and Cahir garda stations on suspicion of dissident republican activity, under section 30 of the Offences against the State Act 1939.
It is believed that two of the detained men were brothers.
The charged pair were due to appear at the Special Criminal Court on Saturday night.
The third man was released without charge on Saturday. A file will be prepared for the Director of Public Prosecutions.