The commission of investigation into the Irish Bank Resolution Corporation (IBRC) is likely to assess the oversight of the Department of Finance on transactions resulting in a loss of at least €10 million.

The inquiry is expected to examine if the department exercised its oversight role but sources said this is unlikely to focus on relationships between senior figures in each organisation.

The cut off date for the inquiry is February 2013, when the IBRC was liquidated. However, outstanding issues past that date with loans being examined by the inquiry can be dealt with, sources indicated.

The prospect of an interim report by October was understood to be ruled out by Minister for Finance Michael Noonan in his meetings with the Opposition.

Mr Noonan met Independent TD Catherine Murphy, Sinn Féin deputy leader Mary Lou McDonald and Fianna Fáil leader Micheál Martin this evening.Mr Noonan is due to present the revised terms of reference for the inquiry to Cabinet at its weekly meeting on Tuesday, and the Dáil will debate the scope of the investigation over two days.

It is understood he said an interim report can only be requested once the commission begins its work, but it would not be possible to provide one by October.

The commission will be given a deadline of the end of the year but Fianna Fáil and Sinn Féin raised concerns because of the possibility of an early general election in the autumn.

Government sources claimed it would prove legally difficult to separate out the sale of Siteserv from other issues in order to provide an interim report on just one issue.

However, Mr Noonan said no decisions have been made and stressed that it will be up to the Cabinet to sign off on the terms of reference.

It is also likely responsibility for the commission of investigation will transfer from the Department of Finance because it will be examined by the inquiry. Responsibility may pass to the Department of the Taoiseach.

The inquiry is primarily transaction based, and will cover any which led to a loss of at least €10million to the taxpayer.

While the Opposition had called for lower thresholds of €5 million or €1 million, the department said this would lead to small business loans and some mortgages falling under the inquiry’s remit, which Mr Noonan last week said would be excluded.

However, the judge hearing the inquiry - likely to be retired High Court judge Iarfhlaith O'Neill - has discretion to include whatever loans may be of interest. Information or concerns about loans which fall under the €10 million threshold can be brought to the attention of the inquiry, sources said.

It was claimed by some in Government circles that a request made in Fianna Fáil, although not by leader Michéal Martin, to include the Minister for Finance would mean the role of Brian Lenihan, as well as Michael Noonan, would be included.

A Fianna Fáil request to include IBRC's wealth management unit, a separate legal entity to IBRC, within the inquiry is also expected to be granted. Mr Martin claimed he has received information alleging "significant conflicts of interest" within the unit.

Meanwhile, the interim report of the Fennelly Commission, which deals with the resignation of former GardacCommissioner Martin Callinan, is expected to be distributed to interested parties this week.

The Fennelly Commission will continue its wider work on the issue of the taping of telephone calls at Garda stations.