Lawyers providing expert advice to the Oireachtas Banking Inquiry have been charging the inquiry €264 per hour.
New figures released by the House of the Oireachtas Commission show the banking inquiry's mounting legal costs last year contributed to the commission's payments to counsel and external solicitors increasing more than six-fold from €34,804 in 2013 to €207,227 last year.
Documents released under the Freedom of Information act include invoices lodged by barristers who have advised the Banking Inquiry in the period.
In one instance, Charles Meenan SC charged €264 (ex-Vat) per hour and was paid €5,940 for 22.5 hours work during last September and October.
It comes amid a clash between the inquiry and the Department of Finance over the release of documents relating to the banking crash.
The Irish Independent has learnt that the department has one million pages of documents which have "some relevance" to the night of the bank guarantee and the wider banking crisis.
Derek Moran, secretary general of the department, wrote to the committee twice in the past month.
Mr Moran and his department raised concerns on issues such as the timescale in which documents should be furnished to the committee.
The committee had asked that all records be provided by January 28, but the department feels this timescale is too tight.
Other issues are legal privilege attached to certain documents, and the scope, scale and timeframe of requests.
But in relation to legal fees, another senior counsel, Patrick McCann, lodged two separate invoices, where he billed €6,600 for 25 hours work at €264 per hour. One of the invoices covering the period September 22 to October 6, for €4,224, involved 16 hours' work related to "review papers, research and advice".
In a separate invoice, Mr McCann billed €3,250 last October concerning advice on the Banking Inquiry with regard to Cabinet confidentiality. The invoice was made up of €2,500 for providing an opinion on June 24 last and €750 for attending and advising at a meeting the following day.
A third senior counsel, Conor Dignam, who has advised the Banking Inquiry billed a total of €4,300. The bill is made up of two consultations on July 21 and 30 at €350 per consultation and opinions and advices priced at €1,800 each.
The rates for junior counsel for advising on the Banking Inquiry is lower at €156 per hour. Patricia O'Sullivan Lacy billed €1,716 in October for 11 hours.
Fine Gael senator Martin Conway said: "The rate of €264 per hour does appear to be excessive, but the inquiry is doing very important work and it needs to call on the best legal minds in the country."
Inquiry member, Fianna Fáil Finance spokesman Michael McGrath (inset) said: "I fully accept for any ordinary person struggling to get by, the rates seem extraordinary, I can fully understand that point of view."