Mr Nick Leeson has said Allied Irish Banks (AIB) has failed to learn the lessons of his own case.
Writing in The Mirrornewpaper in Britain, Mr Leeson, who brought down Barings Bank, said: "It's staggering that financial security at these huge firms is so lax.
"Where are the checks and regulatory audits? There has been chapter and verse written about my experience at Barings but all that counts for nothing".
But AIB says the loss of €860 million at its US subsidiary, Allfirst, is nothing like the Leeson affair.
Group chief executive Mr Michael Buckley said: "What Nick Leeson did was cause terminal damage to Barings. Even when we write off that €860 million, we will be making a profit after tax for 2001".
AIB, Ireland's biggest bank, says customers' money will not be affected by the loss of £537 million. An Allfirst spokesman has admitted its controls broke down.
Lawyers for Mr John Rusnak, the trader involved in the scandal, say he has voluntarily met FBI and federal prosecutors after the bank claimed he had gone missing following internal investigations.
PA