Minister for Justice Alan Shatter has said former solicitor Michael Lynn, who fled Ireland over five years ago leaving debts of more than €80 million, is facing extradition proceedings in Brazil.
The 43-year-old is being detained following a bilateral arrangement between Ireland and Brazil.
Minister Shatter welcomed the agreement between the two countries to begin negotiations on a bilateral extradition treaty.
He said they would treat extradition requests from each other on the basis of reciprocity.
The High Court in Dublin issued a warrant for Mr Lynn's arrest and the case was sent to the Garda Bureau of Fraud Investigation.
The Director Public Prosecutions has directed that Mr Lynn face criminal charges.
Mr Lynn has not been seen in Ireland since a warrant was issued for his arrest five years ago after he failed to turn up in the High Court.
He moved between a number of European countries and the US before settling in Brazil.
Mr Lynn owes over €80m to at least ten financial institutions and has multiple mortgages on many of the 148 properties he is involved with.
The High Court has been told that undertakings he gave to banks to provide security for the loans have not been honoured in many cases.
Two years ago, Mr Lynn was granted permanent residency in Brazil following the birth of his son there.
Mr Lynn was arrested in Pernambuco in the northeast of the country.
The Law Society said Mr Lynn had been struck off in 2008 and was fined €2m, which it said remains unpaid.