The former chief of Anglo Irish Bank was arrested today by fraud squad officers after a dawn raid on his home.
Sean FitzPatrick - former chairman and chief executive of the now nationalised bank - was arrested at his house in Greystones, Co Wicklow. He can be held for 12 hours.
The ex-banker stepped down in December 2008 when it emerged he had loans worth €87m with the institution.
Over a period of eight years up to 2007, Mr Fitzpatrick, 61, temporarily transferred loans with Anglo Irish Bank to another bank before the annual report was audited.
It later emerged that the loan reached as much as €129m at one point in 2007.
Officers from the Garda Bureau of Fraud Investigation searched Mr Fitzpatrick's home as part of a continuing operation into alleged financial irregularities.
A garda spokesman said a man in his early 60s was arrested.
"He is being detained under the provisions of section four of the Criminal Justice Act 1984," the spokesman said.
The Financial Regulator last year called on the GBFI to investigate the bank.
Finance minister Brian Lenihan said: "I have always stated that there is an extensive garda investigation under way. I have been cautious not to prejudice that investigation and am eager to see justice take its course."
Earlier this month Anglo Irish Bank began legal action against Mr FitzPatrick to try to recover loans of €70m.
Former finance minister Alan Dukes, incoming head of state-run Anglo Irish Bank, has said the court case would be treated in the same way as any other debt.
© Press Association