The Northern Bank has announced that it is to move 40 employees from its headquarters in Belfast city centre following last month's robbery.
Staff will be relocated to new positions within the bank
Staff will be relocated to new positions within the bank, either in other departments or branches.
The bank has said the move is being made to safeguard the welfare of staff.
The Irish Bank Officials Association said discussions regarding the transfer of staff have been ongoing since the robbery took place.
The 40 employees make up all of the staff in the bank's cash centre.
The bank has written to all staff. In the confidential letter - which has been seen by the BBC - the bank says the personal security of staff is one of its main priorities.
The Northern Bank has emphasised the relocation has nothing to do with concerns that any confidential information may have been given to the gang who carried out the robbery.
The bank has not said when the move will happen, only that it will happen as soon as is operationally possible.
It said it recognised this was unsettling for the people involved, but under the circumstances, it believed the measure was necessary as a precaution.
The PSNI said £26.5m was taken in the raid on the Northern Bank headquarters in Belfast on 20 December.
On Monday, the Northern Ireland secretary and the Irish foreign minister said they were 100% convinced the IRA was involved in the robbery.
It follows an assessment by PSNI Chief Constable Hugh Orde blaming the paramilitary group.