Former solicitor Michael Lynn, who faces more than 20 charges of alleged theft, is due to be extradited from Brazil next week, the High Court has been told.
The court heard that Mr Lynn expects to be extradited to Ireland on 28 February.
Mr Lynn is looking for a declaration from the High Court that his time in a Brazilian prison will be taken into account if he is convicted in Ireland.
Senior Counsel Michael O'Higgins said his side got word of the impending extradition late last night.
Mr Lynn failed to turn up in the High Court in 2007 and left the country leaving behind an estimated €80 million in debts.
He is being held at Cotel remand prison in Recife in northwest Brazil.
He has been in prison since 2013 when Brazilian federal police, acting on behalf of Interpol, arrested him.
His High Court challenge relates to an offer by the Director of Public Prosecutions to Brazil of a guarantee that Mr Lynn's time served in that country would be offset against any prison term he might get in Ireland if convicted.
Mr O'Higgins told the court that Irish authorities have no legal power to do that and Mr Lynn needs a declaration from the High Court.
Senior Counsel Sean Gillane, for the DPP, argued the proceedings should be dismissed and that the High Court was being "lassoed" into the Brazilian proceedings.
Mr Justice Michael McGrath reserved judgment.
He said he hopes to rule by Friday, given the extradition is scheduled for 28 February.