The chairman of the Public Accounts Committee, Seán Fleming, has warned of "potential risks" to future Exchequer revenues if the Revenue Commissioners and Department of Finance do not clarify the extent and cost of repeated losses carried forward by companies, including banks, which could significantly reduce our corporate tax take.
Mr Fleming was commenting on a series of recommendations, including a proposed sunset clause limiting the capacity of banks to offset historic losses against their current tax bills - effectively allowing them to pay no corporation tax indefinitely - contained in a new draft report on Ireland's corporation tax regime.
Finance Minister Paschal Donohoe has previously stated that he doesn't intend to change how losses are taxed for Irish banks as such a move could adversely affect banks' share prices and could trigger further capital shortfalls on the banks' balance sheets.
The current rules on "deferred tax assets" mean that AIB and Bank of Ireland, which both made over a €1bn in profit last year, will not be liable to pay corporation tax here for at least 20 years.
Some €218bn in trading losses by a variety of sectors were carried forward at the end of 2015 to be offset against future corporation tax liabilities, a figure which the draft report on the examination of matters in relation to receipts from Corporation Tax describes as "alarming".
Almost 60pc of the losses related to the financial and insurance activities sector, with almost €10bn carried forward by the construction sector.
The PAC was informed that the €218bn in losses carried forward at the end of 2015 comprised actual trading losses and unused capital allowances.
However, when the committee requested a breakdown of the losses figures into these two components, Revenue informed the committee it was unable to provide the analysis requested.
"We need to know how far back companies are carrying forward trading losses," said Mr Fleming, who added that many countries have restrictions on how far back historic trading losses can be carried forward.
"There are potential risks to future revenues if we don't analyse and get a hold on this now," he added.
The draft report, circulated to committee members last Friday, says that Revenue data is lacking in detail on the breakdown of such losses carried forward.
The draft report, which will be discussed in detail by the oversight committee in the coming weeks, says that Revenue should put in place procedures to analyse losses carried forward in order to identify those relating to trading losses and those relating to unused capital allowances. It also recommends that Revenue carry out an age analysis of current losses carried forward and put in place procedures to ensure that such an analysis is carried out on a regular and systematic basis.
The draft report says the highly concentrated nature of corporation tax receipts represents an "unacceptable level of risk to the sustainability of the corporation tax regime and to overall Exchequer income".
It also urges the Department of Finance to carry out a review of Ireland's Real Estate Investment Trust (REIT) regime to ensure that domestic and EU ownership is being encouraged appropriately.
The draft report also recommends changes to R&D relief schemes to promote growth among Irish indigenous businesses.