A Labour Junior Minister Kathleen Lynch says Frank Flannery "needs" to appear before the Public Accounts Committee.
He works as a Fine Gael strategist, but is also a director at the Rehab charity.
He is facing calls to answer politicians' questions after weekend reports claiming Rehab paid him to lobby the Government on a range of issues.
This morning Junior Health Minister Lynch declined to say if Mr Flannery should resign either role, before more information is released.
She also rejected the idea that Labour would be "jumping up and down" at this point if Fianna Fáil were at the centre of the controversy.