The Supreme Court has been told that crucial new evidence has emerged about Seán Quinn Jnr.
It claims the evidence shows that Mr Quinn Jnr continued to have control over companies in the Quinn group right up to and throughout a High Court case for contempt earlier this year.
Lawyers for IBRC said based on new evidence, it does not accept the Quinns had lost control of the companies as claimed in the High Court.
Senior counsel Paul Gallagher said the asset-stripping conspiracy was done by a means "so serious and so undermining of the rule of law that it was without parallel".
IBRC told the Supreme Court the evidence recovered from a computer hard drive in Russia shows Seán Quinn Jnr was aware of and played an active role in companies involved in removing assets beyond the reach of the bank.
IBRC claims the new documents show he was a key decision-maker, right up to the time he was jailed for contempt.
This contradicts Mr Quinn Jnr's evidence to the High Court that his involvement with the companies had ended a year before.
The evidence emerged on the second day of a Supreme Court appeal by Mr Quinn Jnr against his jailing for contempt for failing to comply with orders to reverse an asset-stripping conspiracy in the Quinn's International Property Group.
His lawyers say the decision by the High Court to jail him for contempt and his continued detention is legally wrong.
However, IBRC told the court today that Mr Quinn Jnr played a far more active role in the Quinn companies than he admits.
Mr Gallagher said Peter Darragh Quinn had carried out the asset-stripping scheme on behalf of all the Quinns.
Evidence retrieved from a damaged computer hard drive in Russia shows contracts were created allowing for multi-million euro payments to Quinn family members at a time when High Court injunctions were in place.
It is also claimed that efforts were made to back-date the contracts to make it appear they were generated before the High Court orders.
Mr Gallagher said this case was about the rule of law and the administration of justice. Fraudulent transactions had taken place, documents had been back-dated and bogus reports were produced, all designed to implement an asset-stripping scheme and the court was now being asked to ignore it.