Inquiry must call witnesses from North - Howlin

Mr Howlin made the remark in his submission to Taoiseach Enda Kenny, who sought the views of Opposition parties and TDs on the format of the planned inquiry into the sale of Nama's northern loan book.

Mr Howlin said any inquiry should focus on whether or not the integrity of the Project Eagle sale process was "compromised or sought to be compromised" and "if it was, did any such attempt impact on the sale price ultimately achieved?"

He also said that the separate criminal investigations examining elements of the controversial deal must have a cross-border approach.

Mr Howlin said he believes the best way to do this is to set up a "special joint investigation policing team" to investigate the allegations relating to Project Eagle. Fianna Fáil leader Micheál Martin also noted the importance of Northern cooperation with the inquiry.

"It would of course be very helpful if those involved in the North in the sale of Project Eagle were invited and agreed to attend the Inquiry," he said.

Independent TD Mick Wallace, who has been vocal on the issue in the Dáil, said the inquiry should have the powers of compellability of witnesses similar to those of the IBRC Commission of Investigation.

He said the key issue at the centre of the controversy is "the alleged unauthorised leaking and use of confidential Nama information for private gain and whether this caused a loss for the Irish people".

Sinn Féin said the inquiry should be wider than Project Eagle and look into Nama's full operations, while the Social Democrats and Green Party also made submissions.

A separate report by the Comptroller and Auditor General found Nama incurred a potential loss to the taxpayer of £190m (€223m) in the Project Eagle sale. Nama has rejected this report.

A government spokesman said: "All submissions will be given serious consideration before government decides how to proceed."