A senior member of the staff of the former Labour Party leader, Mr Dick Spring, is understood to have had written correspondence after the 1994 European elections with Woodchester Bank about a £24,000 loan taken out with the bank to fund the campaign of Ms Orla Guerin.
The loan was personally guaranteed by Mr Spring and three of his political associates, Mr Fergus Finlay, Mr John Rodgers and Mr Greg Sparks.
Mr Finlay said last week there had been no "nasty letters" between the guarantors and Woodchester before the bank's decision in 1996 to write off the debt.
The claim is understood to have generated concern at Woodchester that its other customers might assume it had not sought the recovery of the Guerin loan and had given preferential treatment to those who guaranteed the loan.
A spokesman for Woodchester said yesterday the bank was seriously concerned at the "repeated inaccurate and misleading assertions that it did not apply its normal rigorous procedures in the management of this loan. It did, and all such procedures, including correspondence, are fully documented and recorded".
The Woodchester file on the Guerin loan is understood to contain two-way correspondence between the bank and a member of the staff of Mr Spring, who was Tanaiste at the time.
This correspondence is believed to date from just after the June 1994 European elections until early 1996, when the debt was written off. This correspondence was described by one source as "normal banking letters concerning debt recovery".
At the same time, the Labour Party sought political donations from up to 1,000 businesses around the State, including Woodchester. Following this fund-raising approach, the bank agreed to cancel the sum outstanding on the Guerin loan by means of a £28,000 donation to Labour.
This amount cancelled out the £24,000 loan and £4,000 interest owed to Woodchester by Mr Spring, Mr Finlay, Mr Rodgers and Mr Sparks. On the RTE television programme The Week In Politics last night Mr Spring said he never sought the cancellation of the loan.
It is understood that Woodchester never issued a cheque to Labour for the £28,000 donation.