Lawyers for the state-owned IBRC, formerly Anglo Irish Bank, allege that files retrieved from the smashed computer in Moscow indicate employment contracts had been created to allow for multi-million severance payments to members of the Quinn family.
The Bank's legal team were making their arguments during Sean Quinn Jnr's appeal against his three-month jail term.
The appeal had initially been expected to last two days. However it is likely it will now run into the beginning of next week.
In the Supreme Court today Senior Counsel said the existence of the contracts had previously been denied by the Quinns..
The Bank's legal team submitted that the material gleaned from the hard-drive shows Mr Quinn Jnr, had been aware of "deliberate backdating" of the employment contracts, signed weeks before a High Court issued orders which banned any interference by the Quinns with their international property group (IPG).
Furthermore, the team said he had been head of a Russian company in March this year - a time when he told the High Court he had no control over it, nor could he retrieve money or information from it.
IBRC's lawyers submitted that these matters should be taken into account or else the appeal would be dealt with on the basis of "absolutely and utterly false" information.
Mr Quinn Jnr has remained at the Training Unit of Mountjoy Prison since his imprisonment in July.
On Tuesday this week, the first day of the appeal, his lawyers argued that his imprisonment had been "incorrect and legally wrong".
They claimed the 33-year-old had been made "hostage to the chieftan", his father, in order to place pressure on him to co-operate with IBRC.