AIB is moving 1,000 employees from city-centre branches to its head office in south Dublin in a bid to make savings of €18m.
The bank revealed the savings targets in an internal email sent out by its transformations director Keith Davies last week.
The email stated that the first staff will be leaving offices in the Docklands' Riverside buildings and the IFSC by mid-2012. Both buildings are currently leased by AIB.
Mr Davies said the moves would "increase our ability to work together as a single team" and make the bank's headquarters in Ballsbridge a "more dynamic working environment".
The transfer of staff is being viewed as a more tangible part of a radical transformation which will see the bank shrink its size.