Under the inquiry’s schedule of work, all interviews with witnesses — including bankers, members of the media, property experts, economists, and politicians — must be concluded by July before the cross-party group publishes its report in November.
Four more tranches of interviewees are still to be called, including those involving politicians and senior civil servants.
While banking inquiry officials have declined to publicly name these individuals until they are told about their impending appearances, it is understood the politician meetings will take place in early July.
Among those to be spoken to at this time will be former taoisigh Mr Ahern and Mr Cowen, who was also finance minister at the height of the boom, and the ex-secretaries general of the Department of Finance David Doyle and Kevin Cardiff.
Speaking on RTÉ Radio earlier this week, banking inquiry chair and Labour TD for Cork South Central, Ciarán Lynch, said he expects that all future interviewees will be told to appear “in the next four weeks”.
He said all witnesses whose appearance has been requested so far have given “full co-operation”, and that any future witnesses are legally obliged to do so under the second stage of the inquiry’s compilability rules.
Speaking in January, Mr Ahern said he would be willing to go before the banking inquiry “if I’m asked”.
The former Fianna Fáil leader said he would like the cross-party investigation to “just get on with it” as the issues he believes are relevant “happened in 2007 to 2008”, more than half a decade ago.
The interviews with Mr Ahern and Mr Cowen will be preceded by other high-profile meetings in the coming weeks with senior bankers and the disgraced former financial regulator, Patrick Neary.
However, while a meeting with ex-ECB president Jean Claude Trichet has been pencilled in for April 30, both parties are still negotiating what this will entail.