Bankrupt Fermanagh businessman Sean Quinn's family will bring separate lawsuits against the Republic's Department of Finance and Central Bank.
The family is already involved in a €2.34bn (£2bn) case against the former Anglo Irish Bank.
The move means the actions of the financial regulators relating to the loans will now be subject to scrutiny by the Irish courts.
Patricia Quinn and her five children yesterday withdrew their application to join the department and Central Bank, in their capacity as regulators, to their action against IBRC.
The Quinns will now issue separate proceedings against the department and bank and will apply to Dublin's Commercial Court to have the case fast-tracked.
They will then apply to have similar issues in that case, and in the Anglo case, heard together.