Chairman of the Public Accounts Committee John McGuinness has called on Frank Flannery to come before the committee following newspaper reports about his lobbying efforts on behalf of the charity Rehab.
It is understood that Rehab will finalise a comprehensive submission for the PAC early next week, following which it is expected that Mr Flannery will address any outstanding issues.
Newspaper reports suggested that the Fine Gael party strategist had been paid by Rehab to lobby the Government on its behalf.
Mr McGuinness said it was unacceptable that Mr Flannery had not yet appeared before the PAC.
He added that these latest developments were undermining the whole charity sector.
Minister for European Affairs Paschal Donohoe also called on Mr Flannery to appear before the PAC.
Speaking on RTÉ Radio, Mr Donohoe said Mr Flannery - and anybody associated with Rehab - should go in front of the committee to establish if public money was involved.
He said: "This is why I believe there should be absolute transparency on all levels of contact between anybody who's involved in a State body, or not, and the State itself.
Mr Flannery and anybody associated with Rehab should go in front of the Public Accounts Committee, they should answer questions like this and I believe it's particularly important to establish if public money was involved in any of this".