IBRC has decided not to charge distressed borrowers interest on the warehoused portion of their home loans in a split mortgage arrangement, RTÉ News has learned.
The bank, which is in liquidation, has 13,500 mortgage holders.
However, its level of arrears is almost three times the industry average.
Under a split mortgage arrangement a portion of a loan is parked while the borrower continues to service the remaining part of the loan.
Bank of Ireland will charge full interest on the warehoused portion of the loan while AIB is to charge no interest and Permanent TSB will charge 1%.
Critics say Bank of Ireland's policy to charge full interest means its offer will be of no help to distressed borrowers.
IBRC's mortgage loan book was originally part of Irish Nationwide.
The loan book will be put up for sale later this year as part of the liquidation of the bank.