Figures provided by Finance Minister Michael Noonan confirm that Nama last year paid out a total of €21.66m in legal fees.
The figures show that over €2m was paid to McCann Fitzgerald across a range of headings.
The Dublin head-quartered legal firm comprises some 62 partners and 290 lawyers and professional staff.
The largest spend in the figures was legal costs incurred by Nama debtors.
The figures, supplied in a written Dáil response to Sinn Féin TD Pearse Doherty, show that a total of €17.7m was incurred by Nama borrowers.
According to Mr Noonan: “Where the borrower is in a position to repay such costs Nama will seek the repayment in cash.
“To the extent the borrower is not in a position to repay those costs, Nama will add these costs to the borrower’s debt obligations to Nama.
“Such costs have been taken as an impairment charge as necessary in Nama’s financial statements.”
Nama spent €3.279m on direct legal costs last year concerning the management of its portfolio of loans.
Arthur Cox solicitors received €473,000; Matheson Ormsby Prentice received €403,000; Simmons & Simmons received €320,000, and A&L Goodbody solicitors were paid €301,000 under that heading.
The figures also show that Eugene F Collins received €272,000; Paul Screenan received €169,000, and Cian Ferriter received €129,000.
Nama incurred €684,000 in due diligence costs, Mr Noonan confirmed, with Hogan Lovells International receiving €144,000 under this heading.
Arthur Cox and Arthur Cox Northern Ireland received a combined €187,000 for due diligence work.
The figures show that under the heading of legal costs incurred by Nama debtors, the largest amount of €1.7m was paid to McCann Fitzgerald.
The firm received an additional €273,000 for legal work carried out on behalf of Nama and an additional €26,000 on due diligence work.
Other top amounts incurred by Nama debtors last year include €1.23m paid to William Fry Solicitors; €1.16m to A&L Goodbody Solicitors; €1.14m to Hogan Lovells International; €1.1m to Eversheds O’Donnell Sweeney, and €1m to DLA Piper UK.