By Padraic Halpin

DUBLIN (Reuters) - The Irish state agency in charge of attracting foreign investment has been in touch with firms considering relocating from London for months and could now reap the benefits post-Brexit, its chief executive said on Friday.

While Ireland is considered to have more to lose than fellow European Union member states by Britain's decision to quit the bloc, the possibility that firms keen to stay in the EU could choose Dublin as their new home offers some potential upside.

Ireland already attracts many multinationals every year, from Apple <AAPL.O> to Citigroup <C.N>, in a hugely successful regime that accounts for almost one in 10 Irish jobs.

"We're not starting from scratch today in that the IDA has a lot of its homework done, we have been engaged with clients, as we are all of the time, over the last couple of months and some of those discussions were around Brexit," IDA Ireland CEO Martin Shannahan told Reuters in a telephone interview.

"You'll know from statements that some very large companies and some very large financial companies in particular have made clear in the last two days that Ireland is being considered. Suffice to say, some companies have short lists and have publicly stated that Ireland is part of their consideration."

Morgan Stanley President Colm Kelleher told Bloomberg Television on Wednesday that Brexit could prompt it to move its European headquarters to Dublin or Frankfurt from London.

Ireland is one of the world's largest centers for services like fund administration - so-called "back office" banking functions, many of which are farmed out from London - and houses sizeable operations for Citi and Credit Suisse <CSGN.S>, which opened its first trading floor in Ireland this year.

As well as Frankfurt, Dublin faces competition from another far bigger center in Paris in its bid to woo British-based bankers, but Shannahan said it will keep casting a wide net.

"Ireland is attractive in any event. The context has just changed a little today and some of those pluses that we have are probably even bigger pluses now, particularly our access to the European market," said Shannahan, who spent the last two days meeting potential clients in New York.

"The opportunities are across all sectors but it would be fair to say financial services features heavily. The potential is difficult to size at this point. What we don't know is what level of access the UK will have to the EU market and that to some extent will dictate the level of potential."

(Reporting by Padraic Halpin; Editing by Dominic Evans)