US banking giant JP Morgan is in advanced negotiations about a project which could see as many as 500 extra staff added to its existing Dublin operation.
The bank currently has 500 staff in the International Financial Services Centre.
While the IDA declined to comment on speculation regarding JP Morgan, a spokesman said "we expect decisions to be made in the middle of this year on Brexit relocation projects".
JP Morgan has not finally committed to increasing its Dublin workforce but negotiations are at an advanced stage.
The bank is planning to move hundreds of London-based staff to offices in Dublin, Frankfurt and Luxembourg in a move that will help secure its EU business after Brexit.
The US banking giant confirmed comments made by Daniel Pinto, head of JP Morgan's corporate and investment bank, who said a "substantial portion of the business" in London will have to be moved to the bloc.
"We are going to use the three banks we already have in Europe as the anchors for our operations," he told Bloomberg on the sidelines of the Euromoney conference in Saudi Arabia.
JP Morgan is expected to set up new hubs in Dublin, Frankfurt and Luxembourg in order to serve EU clients after Brexit, when Britain is expected to lose EU passporting rights for financial services.
Financial passporting is where financial services firms such as banks and insurance companies based in one EU country have the right to provide their services in other EU countries without further authorisation requirements.
"We will have to move hundreds of people in the short-term to be ready for day one, when negotiations finish, and then we will look at the longer-term numbers," Mr Pinto said.
It is understood both front and back office staff will be affected by the relocation drive, which is expected to take place by spring 2019, when the two-year window for Brexit negotiations draws to a close.
Mr Pinto said: "We have to plan for a scenario where there is no UK-EU passporting deal and we have to move a substantial portion of our business to continue serving our European clients."
Meanwhile, Standard Chartered has confirmed it has contacted German regulators about plans to set up a Frankfurt subsidiary that will similarly safeguard its European business.
However, the bank said there would be "minimal" impact on UK staff.
A spokeswoman for Standard Chartered said: "We can confirm that we have decided to progress with an application to set up a European subsidiary in Frankfurt, as we already have a presence in Frankfurt through a branch and our euro-clearing operations.
"This does not mean any change to our UK domicile or a change in our commitment to London.
"We also expect to focus on hiring a small number of staff locally, therefore any impact to UK staff will be minimal."
It follows comments from one of Deutsche Bank's top executives last week, who said nearly half of its own UK-based jobs - equal to about 4,000 front and back office staff - were at risk of being relocated.
A growing list of financial services firms have confirmed relocation plans, with HSBC moving 1,000 staff to France, AIG set to shift a string of executives to Luxembourg and Lloyd's of London opting for a subsidiary in Brussels.
JP Morgan's chief executive Jamie Dimon previously indicated around 4,000 of the bank's 16,000 UK employee base could move as a result of Brexit.
Mr Pinto also addressed staff in a memo at the end of March, saying the bank had spent months weighing up its options and would not rush into any decisions.
US banking peer Citigroup also reached out to its UK workers ahead of the official trigger of Article 50, explaining it was working on the assumption of a "hard Brexit" and was exploring options "with representatives from a number of different countries" as well as clients.
It is unclear how many of Citigroup's near-9,000 UK staff may have to move once a location is chosen.
