The money was taken from the Bank of Ireland at College Green in Dublin
Police in the Irish Republic have recovered up to 4m euros, believed to have come from the country's biggest bank robbery.
On Friday, an armed gang forced a bank official to withdraw an estimated 7m euros (£6.2m) from the Bank of Ireland branch at College Green, Dublin.
They had taken his partner, her mother and a five-year-old boy hostage.
Gardai later arrested six men and a woman for questioning in connection with the robbery.
Detectives have identified a notorious organised crime gang from Dublin's north inner city as the prime suspects.
In a dramatic string of swoops across the Irish capital, one house was raided, two cars were stopped and searched, and cash seized.
The gang had forced their way into the home of Bank of Ireland employee Shane Travers in County Kildare on Thursday night.
His partner, Stephanie Smith, was beaten and the family bundled into a van and driven from the house.
The 24-year-old junior key holder was forced to drive into work early on Friday.
After filling laundry bags with brand new notes from the company's landmark central Dublin branch, he handed the money over to the gang at Clontarf Dart (Dublin Area Rapid Transit) station.
His partner's family were then released in the Ashbourne area of County Meath at around 0700 GMT on Friday.
Police outside the house where the banker's family were held hostage
The Irish justice minister, Dermot Ahern, said he was deeply concerned that proper procedures were not followed at the bank.
"It is a fact that gardai didn't know about this incident until the money had actually left the bank premises.
"Under normal protocol that shouldn't be the case, because the sooner they know about it, the sooner they can put in the necessary checkpoints, etc."
In 2004, a gang forced two employees of the Northern Bank to help it steal £26m from the bank's central Belfast vault.