Some British-based financial services firms have already decided to relocate at least part of their operations to Ireland, and others are expected to follow in the first half of this year, Ireland's minister for the sector said on Tuesday.
Speaking at an event hosted by the London Irish Business Society, Eoghan Murphy said Britain's decision to trigger divorce negotiations from the EU at the end of March had been a catalyst for these moves.
"With the time horizon we now have around Article 50, some decisions have already been made for relocation," Murphy said, declining to name the companies, or give a number.
"We are expecting for some parts of the industry for decisions to be made in Q1 and Q2," he added at the business event in central London.
Earlier this month Irish finance minister Michael Noonan said his central bank had received over 100 inquiries from British-based financial firms considering a move.
Barclays (BARC.L) is preparing to make Dublin its EU headquarters when Britain leaves the European Union, a source familiar with the matter told Reuters on Thursday.
Irish central bank governor Philip Lane said he expected economic ties between Britain and Ireland would remain close after Brexit, and that no other European capital would become a "new London" - though a collection of centers specializing in different financial services was possible.
Britain's government and central bank have highlighted the rest of Europe's reliance on London for financial services, and warned that a tough approach to the Brexit talks from the European Union risked jobs moving to the United States or Asia, rather than elsewhere in Europe.
Murphy told Reuters that some financial services firms wanted to keep quiet their plans to move some operations but leave others to avoid antagonizing British stakeholders.
"Some companies ... are going to be very mindful of the presence they have.
They are not going to be coming out and saying 'Brexit is a disaster, we are moving people to Ireland'."
"So while the decisions have been made and movements will happen they won't necessarily be announced as Brexit decisions, so we can't put numbers on them," he said.
Murphy added that after the two years of formal Brexit talks conclude, he expected there would need to be at least a five-year transitional agreement between the EU and Britain before a complete divorce could take effect.