They can now be questioned by gardaí until tomorrow afternoon.
Meanwhile a woman arrested last night in connection with the robbery is still being detained by gardaí in Killarney.
The armed raid took place at Waterville Post Office at 11 o’clock Wednesday morning.
A manhunt was launched and two men were arrested in the Kilgobnet area of Beaufort in mid Kerry.
Two cars used by the raiders were burned out after they abandoned them.
Two Gardaí were also injured when their car was rammed while in pursuit of the suspects.
The two men who were arrested under Section 30 of the Offences Against the State Act, 1939 have been held at Tralee and Killarney garda stations.
They appeared before a scheduled sitting of Cork District Court today where Killarney gardaí sought an extension of their detention; this was granted.
The men must be charged or released by tomorrow afternoon.
Meanwhile a third person arrested in connection with the raid is still being questioned.
The woman in her late 20s was taken into custody last night, and is being detained at Killarney Garda station under Section 30 of the Offences Against the State Act, 1939.