The Mahon Tribunal is reportedly investigating a number of payments to the Taoiseach, Bertie Ahern, totalling between €50,000 and €100,000.
Reports this morning say businessman David McKenna and a number of other people have been contacted by the tribunal to shed some light on the situation.
The reports say Mr Kenna has been asked for a detailed statement on who requested the money he gave to Mr Ahern, why it was required, who it was given to and whether it was in cash or another form.
The payment was made in 1993, when Mr Ahern was Minister for Finance and treasurer of Fianna Fail.
The tribunal has reportedly been told that the money was used to pay legal bills incurreed by Mr Ahern at the time.