The probe is believed to be connected to a spectacular pre-Christmas bank heist in Belfast, blamed by police on the Irish Republican Army, the main Catholic paramilitary group in Northern Ireland.
Conroy told a press conference that six men and a woman who were arrested in the raids were being held under anti-terrorist laws on suspicion of being members of an "illegal organisation."
Asked by reporters if the illegal organisation was the Provisional IRA, Conroy replied: "Yes and there is also a dissident (republican) individual involved."
Asked if any of the cash had been connected to the bank heist in Belfast in Northern Ireland, Conroy said the investigation was still at an early stage.
"We see a subversive involvement in the movement of this money," Conroy said.
"We are following quite a number of lines as to where the money may have come from. Naturally enough one of those would be in relation to the Northern Ireland bank robbery," Conroy said.
Both the authorities in Ireland and Northern Ireland have blamed the Irish Republican Army of being behind the 26.5 million pounds taken in the December 20 Northern Bank robbery.
Senior Northern Irish police officers were travelling to Dublin on Friday to examine currency, Conroy said.